82 The Chemical Earth82 The Chemical Earth

Focus 1Focus 1

The living and non-living components The living and non-living components of the Earth contain mixturesof the Earth contain mixtures

Balancing Chemical EquationsBalancing Chemical Equations Write the unbalanced equationWrite the unbalanced equation

Chemical formulas of reactants are listed on the left-hand side of the equation Chemical formulas of reactants are listed on the left-hand side of the equation Products are listed on the right-hand side of the equation Products are listed on the right-hand side of the equation Reactants and products are separated by putting an arrow between them to show Reactants and products are separated by putting an arrow between them to show

the direction of the reaction Reactions at equilibrium will have arrows facing both the direction of the reaction Reactions at equilibrium will have arrows facing both directions directions

Balance the equationBalance the equation Apply the Law of Conservation of Mass to get the same number of atoms of every Apply the Law of Conservation of Mass to get the same number of atoms of every

element on each side of the equation Tip Start by balancing an element that element on each side of the equation Tip Start by balancing an element that appears in only appears in only oneone reactant and product reactant and product

Once one element is balanced proceed to balance another and another until all Once one element is balanced proceed to balance another and another until all elements are balanced elements are balanced

Balance chemical formulas by placing coefficients in front of them Balance chemical formulas by placing coefficients in front of them Do not add Do not add subscripts because this will change the formulas subscripts because this will change the formulas

Indicate the states of matter of the reactants and productsIndicate the states of matter of the reactants and products Use (g) for gaseous substances Use (g) for gaseous substances Use (s) for solids Use (s) for solids Use (l) for liquids Use (l) for liquids Use (aq) for species in solution in water Use (aq) for species in solution in water Write the state of matter immediately following the formula of the substance it Write the state of matter immediately following the formula of the substance it

describesdescribes

Source Source httpchemistryaboutcom

Balancing Chemical EquationsBalancing Chemical Equations Write the unbalanced equationWrite the unbalanced equation

Chemical formulas of reactants are listed on the left-hand side of the equation Chemical formulas of reactants are listed on the left-hand side of the equation Products are listed on the right-hand side of the equation Products are listed on the right-hand side of the equation Reactants and products are separated by putting an arrow between them to show Reactants and products are separated by putting an arrow between them to show

the direction of the reaction Reactions at equilibrium will have arrows facing both the direction of the reaction Reactions at equilibrium will have arrows facing both directions directions

Balance the equationBalance the equation Apply the Law of Conservation of Mass to get the same number of atoms of every Apply the Law of Conservation of Mass to get the same number of atoms of every

element on each side of the equation Tip Start by balancing an element that element on each side of the equation Tip Start by balancing an element that appears in only appears in only oneone reactant and product reactant and product

Once one element is balanced proceed to balance another and another until all Once one element is balanced proceed to balance another and another until all elements are balanced elements are balanced

Balance chemical formulas by placing coefficients in front of them Balance chemical formulas by placing coefficients in front of them Do not add Do not add subscripts because this will change the formulas subscripts because this will change the formulas

Indicate the states of matter of the reactants and productsIndicate the states of matter of the reactants and products Use (g) for gaseous substances Use (g) for gaseous substances Use (s) for solids Use (s) for solids Use (l) for liquids Use (l) for liquids Use (aq) for species in solution in water Use (aq) for species in solution in water Write the state of matter immediately following the formula of the substance it Write the state of matter immediately following the formula of the substance it

describesdescribes

Source Source httpchemistryaboutcom

Balancing Chemical Balancing Chemical EquationsEquations

Try these examplesTry these examples

1)Mg + O1)Mg + O2 2 MgO MgO

2)Zn + HCl 2)Zn + HCl ZnCl ZnCl2 2 + H+ H22

3)CaCO3)CaCO33 CaO + CO CaO + CO22

Balancing Chemical EquationsBalancing Chemical Equations

1)2Mg + O1)2Mg + O2 2 2MgO 2MgO Balanced Balanced

2)Zn + 2HCl 2)Zn + 2HCl ZnCl ZnCl2 2 + H+ H22 BalancedBalanced

3)CaCO3)CaCO33 CaO + CO CaO + CO22 BalancedBalanced

Elements Compounds and Elements Compounds and MixturesMixtures

-Elements -Elements are made of one type of atom and cannot are made of one type of atom and cannot be broken down into simpler substancesbe broken down into simpler substances Examples Iron(Fe) Oxygen(OExamples Iron(Fe) Oxygen(O22))

-Compounds -Compounds are pure homogeneous substances are pure homogeneous substances that can be broken down into simpler substances that can be broken down into simpler substances are made of two or more elements and always are made of two or more elements and always have elements in the same ratio by masshave elements in the same ratio by mass Examples table salt (NaCl) pure water (HExamples table salt (NaCl) pure water (H22O)O)

-Mixtures-Mixtures contain two or more pure substances that contain two or more pure substances that are sometimes heterogeneous and can be are sometimes heterogeneous and can be separated by physical means such as filtering separated by physical means such as filtering boiling or the use of a magnetboiling or the use of a magnet Examples iron Examples iron filings in sand sugar dissolved in waterfilings in sand sugar dissolved in water

The Spheres of the EarthThe Spheres of the EarthThe names of the four spheres are derived from the Greek words for stone (litho) air The names of the four spheres are derived from the Greek words for stone (litho) air

(atmo) water (hydro) and life (bio) (atmo) water (hydro) and life (bio)

LithosphereLithosphereThe lithosphere is the solid rocky crust covering entire planet This crust is inorganic The lithosphere is the solid rocky crust covering entire planet This crust is inorganic

and is composed of minerals It covers the entire surface of the earth from the top of and is composed of minerals It covers the entire surface of the earth from the top of Mount Everest to the bottom of the Mariana Trench Mount Everest to the bottom of the Mariana Trench

HydrosphereHydrosphereThe hydrosphere is composed of all of the water on or near the earth This includes the The hydrosphere is composed of all of the water on or near the earth This includes the

oceans rivers lakes and even the moisture in the air Ninety-seven percent of the oceans rivers lakes and even the moisture in the air Ninety-seven percent of the earths water is in the oceans The remaining three percent is fresh water three-earths water is in the oceans The remaining three percent is fresh water three-quarters of the fresh water is solid and exists in ice sheetsquarters of the fresh water is solid and exists in ice sheets

BiosphereBiosphereThe biosphere is composed of all living organisms Plants animals and one-celled The biosphere is composed of all living organisms Plants animals and one-celled

organisms are all part of the biosphere Most of the planets life is found from three organisms are all part of the biosphere Most of the planets life is found from three meters below the ground to thirty meters above it and in the top 200 meters of the meters below the ground to thirty meters above it and in the top 200 meters of the oceans and seas oceans and seas

AtmosphereAtmosphereThe atmosphere is the body of air which surrounds our planet Most of our atmosphere The atmosphere is the body of air which surrounds our planet Most of our atmosphere

is located close to the earths surface where it is most dense The air of our planet is is located close to the earths surface where it is most dense The air of our planet is 79 nitrogen and just under 21 oxygen the small amount remaining is composed 79 nitrogen and just under 21 oxygen the small amount remaining is composed of carbon dioxide and other gasses of carbon dioxide and other gasses

Source Source httpgeographyaboutcomodphysicalgeographyafoursphereshtm

Balancing Chemical EquationsBalancing Chemical Equations

1)2Mg + O1)2Mg + O2 2 2MgO 2MgO Balanced Balanced

2)Zn + 2HCl 2)Zn + 2HCl ZnCl ZnCl2 2 + H+ H22 BalancedBalanced

3)CaCO3)CaCO33 CaO + CO CaO + CO22 BalancedBalanced

Elements Compounds and Elements Compounds and MixturesMixtures

-Elements -Elements are made of one type of atom and cannot are made of one type of atom and cannot be broken down into simpler substancesbe broken down into simpler substances Examples Iron(Fe) Oxygen(OExamples Iron(Fe) Oxygen(O22))

-Compounds -Compounds are pure homogeneous substances are pure homogeneous substances that can be broken down into simpler substances that can be broken down into simpler substances are made of two or more elements and always are made of two or more elements and always have elements in the same ratio by masshave elements in the same ratio by mass Examples table salt (NaCl) pure water (HExamples table salt (NaCl) pure water (H22O)O)

-Mixtures-Mixtures contain two or more pure substances that contain two or more pure substances that are sometimes heterogeneous and can be are sometimes heterogeneous and can be separated by physical means such as filtering separated by physical means such as filtering boiling or the use of a magnetboiling or the use of a magnet Examples iron Examples iron filings in sand sugar dissolved in waterfilings in sand sugar dissolved in water

The Spheres of the EarthThe Spheres of the EarthThe names of the four spheres are derived from the Greek words for stone (litho) air The names of the four spheres are derived from the Greek words for stone (litho) air

(atmo) water (hydro) and life (bio) (atmo) water (hydro) and life (bio)

LithosphereLithosphereThe lithosphere is the solid rocky crust covering entire planet This crust is inorganic The lithosphere is the solid rocky crust covering entire planet This crust is inorganic

and is composed of minerals It covers the entire surface of the earth from the top of and is composed of minerals It covers the entire surface of the earth from the top of Mount Everest to the bottom of the Mariana Trench Mount Everest to the bottom of the Mariana Trench

HydrosphereHydrosphereThe hydrosphere is composed of all of the water on or near the earth This includes the The hydrosphere is composed of all of the water on or near the earth This includes the

oceans rivers lakes and even the moisture in the air Ninety-seven percent of the oceans rivers lakes and even the moisture in the air Ninety-seven percent of the earths water is in the oceans The remaining three percent is fresh water three-earths water is in the oceans The remaining three percent is fresh water three-quarters of the fresh water is solid and exists in ice sheetsquarters of the fresh water is solid and exists in ice sheets

BiosphereBiosphereThe biosphere is composed of all living organisms Plants animals and one-celled The biosphere is composed of all living organisms Plants animals and one-celled

organisms are all part of the biosphere Most of the planets life is found from three organisms are all part of the biosphere Most of the planets life is found from three meters below the ground to thirty meters above it and in the top 200 meters of the meters below the ground to thirty meters above it and in the top 200 meters of the oceans and seas oceans and seas

AtmosphereAtmosphereThe atmosphere is the body of air which surrounds our planet Most of our atmosphere The atmosphere is the body of air which surrounds our planet Most of our atmosphere

is located close to the earths surface where it is most dense The air of our planet is is located close to the earths surface where it is most dense The air of our planet is 79 nitrogen and just under 21 oxygen the small amount remaining is composed 79 nitrogen and just under 21 oxygen the small amount remaining is composed of carbon dioxide and other gasses of carbon dioxide and other gasses

Source Source httpgeographyaboutcomodphysicalgeographyafoursphereshtm

Elements Compounds and Elements Compounds and MixturesMixtures

-Elements -Elements are made of one type of atom and cannot are made of one type of atom and cannot be broken down into simpler substancesbe broken down into simpler substances Examples Iron(Fe) Oxygen(OExamples Iron(Fe) Oxygen(O22))

-Compounds -Compounds are pure homogeneous substances are pure homogeneous substances that can be broken down into simpler substances that can be broken down into simpler substances are made of two or more elements and always are made of two or more elements and always have elements in the same ratio by masshave elements in the same ratio by mass Examples table salt (NaCl) pure water (HExamples table salt (NaCl) pure water (H22O)O)

-Mixtures-Mixtures contain two or more pure substances that contain two or more pure substances that are sometimes heterogeneous and can be are sometimes heterogeneous and can be separated by physical means such as filtering separated by physical means such as filtering boiling or the use of a magnetboiling or the use of a magnet Examples iron Examples iron filings in sand sugar dissolved in waterfilings in sand sugar dissolved in water

The Spheres of the EarthThe Spheres of the EarthThe names of the four spheres are derived from the Greek words for stone (litho) air The names of the four spheres are derived from the Greek words for stone (litho) air

(atmo) water (hydro) and life (bio) (atmo) water (hydro) and life (bio)

LithosphereLithosphereThe lithosphere is the solid rocky crust covering entire planet This crust is inorganic The lithosphere is the solid rocky crust covering entire planet This crust is inorganic

and is composed of minerals It covers the entire surface of the earth from the top of and is composed of minerals It covers the entire surface of the earth from the top of Mount Everest to the bottom of the Mariana Trench Mount Everest to the bottom of the Mariana Trench

HydrosphereHydrosphereThe hydrosphere is composed of all of the water on or near the earth This includes the The hydrosphere is composed of all of the water on or near the earth This includes the

oceans rivers lakes and even the moisture in the air Ninety-seven percent of the oceans rivers lakes and even the moisture in the air Ninety-seven percent of the earths water is in the oceans The remaining three percent is fresh water three-earths water is in the oceans The remaining three percent is fresh water three-quarters of the fresh water is solid and exists in ice sheetsquarters of the fresh water is solid and exists in ice sheets

BiosphereBiosphereThe biosphere is composed of all living organisms Plants animals and one-celled The biosphere is composed of all living organisms Plants animals and one-celled

organisms are all part of the biosphere Most of the planets life is found from three organisms are all part of the biosphere Most of the planets life is found from three meters below the ground to thirty meters above it and in the top 200 meters of the meters below the ground to thirty meters above it and in the top 200 meters of the oceans and seas oceans and seas

AtmosphereAtmosphereThe atmosphere is the body of air which surrounds our planet Most of our atmosphere The atmosphere is the body of air which surrounds our planet Most of our atmosphere

is located close to the earths surface where it is most dense The air of our planet is is located close to the earths surface where it is most dense The air of our planet is 79 nitrogen and just under 21 oxygen the small amount remaining is composed 79 nitrogen and just under 21 oxygen the small amount remaining is composed of carbon dioxide and other gasses of carbon dioxide and other gasses

Source Source httpgeographyaboutcomodphysicalgeographyafoursphereshtm

The Spheres of the EarthThe Spheres of the EarthThe names of the four spheres are derived from the Greek words for stone (litho) air The names of the four spheres are derived from the Greek words for stone (litho) air

(atmo) water (hydro) and life (bio) (atmo) water (hydro) and life (bio)

LithosphereLithosphereThe lithosphere is the solid rocky crust covering entire planet This crust is inorganic The lithosphere is the solid rocky crust covering entire planet This crust is inorganic

and is composed of minerals It covers the entire surface of the earth from the top of and is composed of minerals It covers the entire surface of the earth from the top of Mount Everest to the bottom of the Mariana Trench Mount Everest to the bottom of the Mariana Trench

HydrosphereHydrosphereThe hydrosphere is composed of all of the water on or near the earth This includes the The hydrosphere is composed of all of the water on or near the earth This includes the

oceans rivers lakes and even the moisture in the air Ninety-seven percent of the oceans rivers lakes and even the moisture in the air Ninety-seven percent of the earths water is in the oceans The remaining three percent is fresh water three-earths water is in the oceans The remaining three percent is fresh water three-quarters of the fresh water is solid and exists in ice sheetsquarters of the fresh water is solid and exists in ice sheets

BiosphereBiosphereThe biosphere is composed of all living organisms Plants animals and one-celled The biosphere is composed of all living organisms Plants animals and one-celled

organisms are all part of the biosphere Most of the planets life is found from three organisms are all part of the biosphere Most of the planets life is found from three meters below the ground to thirty meters above it and in the top 200 meters of the meters below the ground to thirty meters above it and in the top 200 meters of the oceans and seas oceans and seas

AtmosphereAtmosphereThe atmosphere is the body of air which surrounds our planet Most of our atmosphere The atmosphere is the body of air which surrounds our planet Most of our atmosphere

is located close to the earths surface where it is most dense The air of our planet is is located close to the earths surface where it is most dense The air of our planet is 79 nitrogen and just under 21 oxygen the small amount remaining is composed 79 nitrogen and just under 21 oxygen the small amount remaining is composed of carbon dioxide and other gasses of carbon dioxide and other gasses

Source Source httpgeographyaboutcomodphysicalgeographyafoursphereshtm

The Spheres of the EarthThe Spheres of the EarthMixtures in the LithosphereMixtures in the Lithosphere--Rocks-mixtures of silicates metals and Rocks-mixtures of silicates metals and

other mineralsother minerals-Sand-mixture of silicon dioxide and shells-Sand-mixture of silicon dioxide and shells-Soils-mixture of clays metals sand -Soils-mixture of clays metals sand

decomposing matterdecomposing matter-Mineral ores-oxides sulfides carbonates -Mineral ores-oxides sulfides carbonates

sulfates and chlorides of metalssulfates and chlorides of metals-Coal oil and natural gas-mixtures of -Coal oil and natural gas-mixtures of

carbon compoundscarbon compounds

Mixtures in the HydrosphereMixtures in the Hydrosphere--Sea water- mixture of water and various Sea water- mixture of water and various

salts such as sodium magnesium and salts such as sodium magnesium and calcium chlorides and other halides calcium chlorides and other halides and sulfatesand sulfates

-Ground water- mixture of water and -Ground water- mixture of water and dissolved chlorides and sulfates and dissolved chlorides and sulfates and suspended mineralssuspended minerals

-Dissolved gases- nitrogen oxygen and -Dissolved gases- nitrogen oxygen and carbon dioxidecarbon dioxide

Mixtures in the BiosphereMixtures in the Biosphere--Blood-mixture of plasma red and white Blood-mixture of plasma red and white

cellscells-Animals plants bacteria-contain -Animals plants bacteria-contain

mixtures of carbon compounds mixtures of carbon compounds (carbohydrates proteins fats and (carbohydrates proteins fats and vitamins)vitamins)

-Water with dissolved minerals-Water with dissolved minerals-Dissolved gases-oxygen nitrogen and -Dissolved gases-oxygen nitrogen and

carbon dioxidecarbon dioxide

Mixtures in the AtmosphereMixtures in the Atmosphere--Mixture of gases- elements of nitrogen Mixture of gases- elements of nitrogen

oxygen argon and a small amount of oxygen argon and a small amount of other gaseous compounds such as other gaseous compounds such as water carbon dioxide carbon water carbon dioxide carbon monoxide sulfur dioxide and nitrogen monoxide sulfur dioxide and nitrogen dioxidedioxide

Separation of MixturesSeparation of Mixtures

SieveSieve

To separate solids of To separate solids of different sizesdifferent sizes

FiltrationFiltration

To separate solids To separate solids and and liquidssolutionsliquidssolutions

Separation of MixturesSeparation of Mixtures

Evaporation (to Evaporation (to dryness)dryness)

To separate dissolved To separate dissolved solids in liquidssolids in liquids

DistillationDistillation

To separate liquids To separate liquids from solutions from solutions (purification)(purification)

Separation of MixturesSeparation of Mixtures

Separating FunnelSeparating FunnelTo separate two To separate two

immiscible liquids and immiscible liquids and for solvent extraction for solvent extraction This technique makes This technique makes use of a difference in use of a difference in densitiesdensities

Separation by solubilitySeparation by solubilityTo separate mixtures of To separate mixtures of

solidssolids One solid is soluble in One solid is soluble in

a solvent and the a solvent and the others are notothers are not

The insoluble The insoluble components are components are removed by filtrationremoved by filtration

Evaporation is used to Evaporation is used to recover the pure recover the pure dissolved substance dissolved substance (solute)(solute)

Separation of MixturesSeparation of MixturesLiquification and Liquification and

fractional distillationfractional distillationTo separate mixtures of To separate mixtures of

gases-gases are cooled gases-gases are cooled to liquefy them to liquefy them followed by fractional followed by fractional distillation Fractional distillation Fractional distillation allows for distillation allows for separation of separation of substances with similar substances with similar boiling points boiling points

Other methods to Other methods to separate gases would separate gases would make use of differences make use of differences in solubility in liquids in solubility in liquids such as watersuch as water

Separation of MixturesSeparation of Mixtures

ChromatographyChromatography is the separation of mixtures by selective adsorption is the separation of mixtures by selective adsorption

(absorbing onto the surface) onto a (absorbing onto the surface) onto a stationary phasestationary phase This This technique is used to sort a mixture out into its separate technique is used to sort a mixture out into its separate componentscomponents

There are several types for various mixtures and they There are several types for various mixtures and they includeinclude

Column chromatography Column chromatography Paper chromatographyPaper chromatography Thin layer chromatographyThin layer chromatography Gas chromatography (GC)Gas chromatography (GC)

All techniques make use of an inert substance such as All techniques make use of an inert substance such as alumina silica or paper The components of a mixture alumina silica or paper The components of a mixture adhere to the inert substance with different strengths adhere to the inert substance with different strengths which leads to separation which leads to separation

Separation of MixturesSeparation of MixturesPaper chromatographyPaper chromatography This is the simplest form of This is the simplest form of

chromatography chromatography The stationary phase is a special The stationary phase is a special

chromatography paper but often filter chromatography paper but often filter paper is used in schools paper is used in schools

The mobile phase is a solvent mixture eg The mobile phase is a solvent mixture eg water and ethanol water and ethanol

The mixture under analysis is placed in a The mixture under analysis is placed in a tiny concentrated dot near the bottom of tiny concentrated dot near the bottom of the paper the paper

The paper is hung with the bottom dipped The paper is hung with the bottom dipped in solvent which rises up the paper to come in solvent which rises up the paper to come in contact with the mixture in contact with the mixture

As the solvent rises further up the paper As the solvent rises further up the paper the components are separated as they are the components are separated as they are swept along swept along

The strip of paper is called a The strip of paper is called a chromatogramchromatogram Identification of the components is based on Identification of the components is based on

RRf values ndash a ratio between the distance f values ndash a ratio between the distance travelled by the component to the distance travelled by the component to the distance travelled by the travelled by the solvent frontsolvent front

Starting line

Solvent Front

Separation of MixturesSeparation of MixturesGas chromatography (GC) Gas chromatography (GC) uses a stationary phase and a uses a stationary phase and a

mobile phase The mobile phase is a mobile phase The mobile phase is a carrier gascarrier gas and the and the stationary phase may be a liquid or a solid GC is a very stationary phase may be a liquid or a solid GC is a very rapid highly sensitive and reliable form of analysis but is rapid highly sensitive and reliable form of analysis but is limited to compounds that can be vaporised without limited to compounds that can be vaporised without decomposing Low-molecular-weight organic compounds decomposing Low-molecular-weight organic compounds are ideal for this sort of analysis The diagram on the right are ideal for this sort of analysis The diagram on the right shows a typical chromatogramshows a typical chromatogram

Separation of Mixtures-summary of Separation of Mixtures-summary of techniquestechniques

Separation MethodSeparation Method Property used to Property used to achieve separationachieve separation

SievingSieving Particle sizeParticle size

FiltrationFiltration One substance is solid the One substance is solid the other is liquid or solutionother is liquid or solution

EvaporationEvaporation Liquid has a much lower Liquid has a much lower boiling point than the solidboiling point than the solid

DistillationDistillation Large difference in boiling Large difference in boiling pointpoint

Fractional DistillationFractional Distillation Smaller difference in boiling Smaller difference in boiling pointpoint

Separating FunnelSeparating Funnel Density (mvol) of immiscible Density (mvol) of immiscible liquidsliquids

Adding a solvent then filtrationAdding a solvent then filtration One substance is soluble in a One substance is soluble in a solvent and the others are notsolvent and the others are not

ChromatographyChromatography Different adsorption to a Different adsorption to a stationary phasestationary phase

Separation of Mixtures-examplesSeparation of Mixtures-examples

Separation MethodSeparation Method Example of useExample of useSievingSieving To separate sand from gravel at a To separate sand from gravel at a

rock quarryrock quarry

FiltrationFiltration Drinking water purification Drinking water purification processesprocesses

EvaporationEvaporation Salt evaporation ponds for table saltSalt evaporation ponds for table salt

DistillationDistillation Obtaining pure water from sea Obtaining pure water from sea waterwater

Fractional DistillationFractional Distillation Separation of crude oil components Separation of crude oil components (petrol diesel kerosene waxes (petrol diesel kerosene waxes etc)etc)

Separating FunnelSeparating Funnel To remove oil from water solvent To remove oil from water solvent extraction in analytical testing (eg extraction in analytical testing (eg pesticides)pesticides)

Adding a solvent then filtrationAdding a solvent then filtration Removal of salt from sand with Removal of salt from sand with waterwater

ChromatographyChromatography Analytical testing (eg water Analytical testing (eg water contaminants)contaminants)

Chemical AnalysisChemical Analysis

TwoTwo general types general types

11 QualitativeQualitative AnalysisAnalysis to determine what substances are present to determine what substances are present

in a samplein a sample

22 QuantitativeQuantitative AnalysisAnalysis to determine how much of each substance to determine how much of each substance

there is in a samplethere is in a sample

Percentage compositionPercentage composition

Quantitative Analysis of a substance involves Quantitative Analysis of a substance involves the determination of actual percentages the determination of actual percentages present in a sample present in a sample

This involves eitherThis involves either11 VolumetricVolumetric analysis-involves measuring analysis-involves measuring

percentages by volumepercentages by volume22 GravimetricGravimetric analysis-involves measuring analysis-involves measuring

percentages by massweightpercentages by massweight

In either case the calculations will be similarIn either case the calculations will be similar

Gravimetric AnalysisGravimetric Analysis

There are a variety of reasons for determining the There are a variety of reasons for determining the composition of a substance in a mixture includingcomposition of a substance in a mixture including

Determining the amount of pollutants present in Determining the amount of pollutants present in drinking waterdrinking water

Determining the amount of a metal present in an Determining the amount of a metal present in an ore sampleore sample

Quality control in the production of a variety of Quality control in the production of a variety of consumer goods (eg ensuring the correct consumer goods (eg ensuring the correct quantities of N P and K in fertilisers) quantities of N P and K in fertilisers)

Soil testing to determine suitability for plantcrop Soil testing to determine suitability for plantcrop growthgrowth

Gravimetric AnalysisGravimetric AnalysisGravimetric analysis involves the use of a variety of Gravimetric analysis involves the use of a variety of

separation techniques followed by a simple calculation to separation techniques followed by a simple calculation to determine the percentage composition of a substancedetermine the percentage composition of a substance

For exampleFor exampleA sample of ore weighing 1063g is found to contain 155g of A sample of ore weighing 1063g is found to contain 155g of

nickel (Ni) and 076g of cobalt (Co) Calculate the nickel (Ni) and 076g of cobalt (Co) Calculate the composition of Ni and Cocomposition of Ni and Co

component = component = mass of component in samplemass of component in sample x 100 x 100 total mass of sampletotal mass of sample

NiNi = 155g1063g x 100 = = 155g1063g x 100 = 14581458

CoCo = 076g1063g x 100 = = 076g1063g x 100 = 715715

Class AssignmentClass Assignment

Choose a mixture from one of the 4 spheres of the Earth and gather Choose a mixture from one of the 4 spheres of the Earth and gather information about the followinginformation about the following

Industrial separation processes to separate the mixtureIndustrial separation processes to separate the mixture The properties of the mixture that are used in these separation The properties of the mixture that are used in these separation

processesprocesses The products of separation and their usesThe products of separation and their uses The issues associated with wastes generated from these The issues associated with wastes generated from these

processesprocesses

Present your information in Report Style with supporting diagrams Present your information in Report Style with supporting diagrams and a source list and a source list

82 The Chemical Earth82 The Chemical Earth

Focus 2Focus 2Although most elements are found in Although most elements are found in

combinations on Earth some elements are combinations on Earth some elements are found uncombinedfound uncombined

Properties of the Properties of the ElementsElements

Elements are classified into three categories based on their Elements are classified into three categories based on their physical propertiesphysical properties

The 3 categories areThe 3 categories are

MetalsMetals Non-metalsNon-metals Semi-metals or metaloidsSemi-metals or metaloids

Some of the physical properties used in this classificationSome of the physical properties used in this classification

Density (massvolume)Density (massvolume) Boiling pointmelting pointBoiling pointmelting point Electrical and Thermal conductivityElectrical and Thermal conductivity State at room temperature (solid liquid or gas)State at room temperature (solid liquid or gas) AppearanceAppearance

The Periodic TableThe Periodic Table

httplibrarytedankarak12trchemistryvol1atomstrtrans50jpg

Separation of MixturesSeparation of Mixtures

SieveSieve

To separate solids of To separate solids of different sizesdifferent sizes

FiltrationFiltration

To separate solids To separate solids and and liquidssolutionsliquidssolutions

Separation of MixturesSeparation of Mixtures

Evaporation (to Evaporation (to dryness)dryness)

To separate dissolved To separate dissolved solids in liquidssolids in liquids

DistillationDistillation

To separate liquids To separate liquids from solutions from solutions (purification)(purification)

Separation of MixturesSeparation of Mixtures

Separating FunnelSeparating FunnelTo separate two To separate two

immiscible liquids and immiscible liquids and for solvent extraction for solvent extraction This technique makes This technique makes use of a difference in use of a difference in densitiesdensities

Separation by solubilitySeparation by solubilityTo separate mixtures of To separate mixtures of

solidssolids One solid is soluble in One solid is soluble in

a solvent and the a solvent and the others are notothers are not

The insoluble The insoluble components are components are removed by filtrationremoved by filtration

Evaporation is used to Evaporation is used to recover the pure recover the pure dissolved substance dissolved substance (solute)(solute)

Separation of MixturesSeparation of MixturesLiquification and Liquification and

fractional distillationfractional distillationTo separate mixtures of To separate mixtures of

gases-gases are cooled gases-gases are cooled to liquefy them to liquefy them followed by fractional followed by fractional distillation Fractional distillation Fractional distillation allows for distillation allows for separation of separation of substances with similar substances with similar boiling points boiling points

Other methods to Other methods to separate gases would separate gases would make use of differences make use of differences in solubility in liquids in solubility in liquids such as watersuch as water

Separation of MixturesSeparation of Mixtures

ChromatographyChromatography is the separation of mixtures by selective adsorption is the separation of mixtures by selective adsorption

(absorbing onto the surface) onto a (absorbing onto the surface) onto a stationary phasestationary phase This This technique is used to sort a mixture out into its separate technique is used to sort a mixture out into its separate componentscomponents

There are several types for various mixtures and they There are several types for various mixtures and they includeinclude

Column chromatography Column chromatography Paper chromatographyPaper chromatography Thin layer chromatographyThin layer chromatography Gas chromatography (GC)Gas chromatography (GC)

All techniques make use of an inert substance such as All techniques make use of an inert substance such as alumina silica or paper The components of a mixture alumina silica or paper The components of a mixture adhere to the inert substance with different strengths adhere to the inert substance with different strengths which leads to separation which leads to separation

Separation of MixturesSeparation of MixturesPaper chromatographyPaper chromatography This is the simplest form of This is the simplest form of

chromatography chromatography The stationary phase is a special The stationary phase is a special

chromatography paper but often filter chromatography paper but often filter paper is used in schools paper is used in schools

The mobile phase is a solvent mixture eg The mobile phase is a solvent mixture eg water and ethanol water and ethanol

The mixture under analysis is placed in a The mixture under analysis is placed in a tiny concentrated dot near the bottom of tiny concentrated dot near the bottom of the paper the paper

The paper is hung with the bottom dipped The paper is hung with the bottom dipped in solvent which rises up the paper to come in solvent which rises up the paper to come in contact with the mixture in contact with the mixture

As the solvent rises further up the paper As the solvent rises further up the paper the components are separated as they are the components are separated as they are swept along swept along

The strip of paper is called a The strip of paper is called a chromatogramchromatogram Identification of the components is based on Identification of the components is based on

RRf values ndash a ratio between the distance f values ndash a ratio between the distance travelled by the component to the distance travelled by the component to the distance travelled by the travelled by the solvent frontsolvent front

Starting line

Solvent Front

Separation of MixturesSeparation of MixturesGas chromatography (GC) Gas chromatography (GC) uses a stationary phase and a uses a stationary phase and a

mobile phase The mobile phase is a mobile phase The mobile phase is a carrier gascarrier gas and the and the stationary phase may be a liquid or a solid GC is a very stationary phase may be a liquid or a solid GC is a very rapid highly sensitive and reliable form of analysis but is rapid highly sensitive and reliable form of analysis but is limited to compounds that can be vaporised without limited to compounds that can be vaporised without decomposing Low-molecular-weight organic compounds decomposing Low-molecular-weight organic compounds are ideal for this sort of analysis The diagram on the right are ideal for this sort of analysis The diagram on the right shows a typical chromatogramshows a typical chromatogram

Separation of Mixtures-summary of Separation of Mixtures-summary of techniquestechniques

Separation MethodSeparation Method Property used to Property used to achieve separationachieve separation

SievingSieving Particle sizeParticle size

FiltrationFiltration One substance is solid the One substance is solid the other is liquid or solutionother is liquid or solution

EvaporationEvaporation Liquid has a much lower Liquid has a much lower boiling point than the solidboiling point than the solid

DistillationDistillation Large difference in boiling Large difference in boiling pointpoint

Fractional DistillationFractional Distillation Smaller difference in boiling Smaller difference in boiling pointpoint

Separating FunnelSeparating Funnel Density (mvol) of immiscible Density (mvol) of immiscible liquidsliquids

Adding a solvent then filtrationAdding a solvent then filtration One substance is soluble in a One substance is soluble in a solvent and the others are notsolvent and the others are not

ChromatographyChromatography Different adsorption to a Different adsorption to a stationary phasestationary phase

Separation of Mixtures-examplesSeparation of Mixtures-examples

Separation MethodSeparation Method Example of useExample of useSievingSieving To separate sand from gravel at a To separate sand from gravel at a

rock quarryrock quarry

FiltrationFiltration Drinking water purification Drinking water purification processesprocesses

EvaporationEvaporation Salt evaporation ponds for table saltSalt evaporation ponds for table salt

DistillationDistillation Obtaining pure water from sea Obtaining pure water from sea waterwater

Fractional DistillationFractional Distillation Separation of crude oil components Separation of crude oil components (petrol diesel kerosene waxes (petrol diesel kerosene waxes etc)etc)

Separating FunnelSeparating Funnel To remove oil from water solvent To remove oil from water solvent extraction in analytical testing (eg extraction in analytical testing (eg pesticides)pesticides)

Adding a solvent then filtrationAdding a solvent then filtration Removal of salt from sand with Removal of salt from sand with waterwater

ChromatographyChromatography Analytical testing (eg water Analytical testing (eg water contaminants)contaminants)

Chemical AnalysisChemical Analysis

TwoTwo general types general types

11 QualitativeQualitative AnalysisAnalysis to determine what substances are present to determine what substances are present

in a samplein a sample

22 QuantitativeQuantitative AnalysisAnalysis to determine how much of each substance to determine how much of each substance

there is in a samplethere is in a sample

Percentage compositionPercentage composition

Quantitative Analysis of a substance involves Quantitative Analysis of a substance involves the determination of actual percentages the determination of actual percentages present in a sample present in a sample

This involves eitherThis involves either11 VolumetricVolumetric analysis-involves measuring analysis-involves measuring

percentages by volumepercentages by volume22 GravimetricGravimetric analysis-involves measuring analysis-involves measuring

percentages by massweightpercentages by massweight

In either case the calculations will be similarIn either case the calculations will be similar

Gravimetric AnalysisGravimetric Analysis

There are a variety of reasons for determining the There are a variety of reasons for determining the composition of a substance in a mixture includingcomposition of a substance in a mixture including

Determining the amount of pollutants present in Determining the amount of pollutants present in drinking waterdrinking water

Determining the amount of a metal present in an Determining the amount of a metal present in an ore sampleore sample

Quality control in the production of a variety of Quality control in the production of a variety of consumer goods (eg ensuring the correct consumer goods (eg ensuring the correct quantities of N P and K in fertilisers) quantities of N P and K in fertilisers)

Soil testing to determine suitability for plantcrop Soil testing to determine suitability for plantcrop growthgrowth

Gravimetric AnalysisGravimetric AnalysisGravimetric analysis involves the use of a variety of Gravimetric analysis involves the use of a variety of

separation techniques followed by a simple calculation to separation techniques followed by a simple calculation to determine the percentage composition of a substancedetermine the percentage composition of a substance

For exampleFor exampleA sample of ore weighing 1063g is found to contain 155g of A sample of ore weighing 1063g is found to contain 155g of

nickel (Ni) and 076g of cobalt (Co) Calculate the nickel (Ni) and 076g of cobalt (Co) Calculate the composition of Ni and Cocomposition of Ni and Co

component = component = mass of component in samplemass of component in sample x 100 x 100 total mass of sampletotal mass of sample

NiNi = 155g1063g x 100 = = 155g1063g x 100 = 14581458

CoCo = 076g1063g x 100 = = 076g1063g x 100 = 715715

Class AssignmentClass Assignment

Choose a mixture from one of the 4 spheres of the Earth and gather Choose a mixture from one of the 4 spheres of the Earth and gather information about the followinginformation about the following

Industrial separation processes to separate the mixtureIndustrial separation processes to separate the mixture The properties of the mixture that are used in these separation The properties of the mixture that are used in these separation

processesprocesses The products of separation and their usesThe products of separation and their uses The issues associated with wastes generated from these The issues associated with wastes generated from these

processesprocesses

Present your information in Report Style with supporting diagrams Present your information in Report Style with supporting diagrams and a source list and a source list

82 The Chemical Earth82 The Chemical Earth

Focus 2Focus 2Although most elements are found in Although most elements are found in

combinations on Earth some elements are combinations on Earth some elements are found uncombinedfound uncombined

Properties of the Properties of the ElementsElements

Elements are classified into three categories based on their Elements are classified into three categories based on their physical propertiesphysical properties

The 3 categories areThe 3 categories are

MetalsMetals Non-metalsNon-metals Semi-metals or metaloidsSemi-metals or metaloids

Some of the physical properties used in this classificationSome of the physical properties used in this classification

Density (massvolume)Density (massvolume) Boiling pointmelting pointBoiling pointmelting point Electrical and Thermal conductivityElectrical and Thermal conductivity State at room temperature (solid liquid or gas)State at room temperature (solid liquid or gas) AppearanceAppearance

The Periodic TableThe Periodic Table

httplibrarytedankarak12trchemistryvol1atomstrtrans50jpg

Separation of MixturesSeparation of Mixtures

Evaporation (to Evaporation (to dryness)dryness)

To separate dissolved To separate dissolved solids in liquidssolids in liquids

DistillationDistillation

To separate liquids To separate liquids from solutions from solutions (purification)(purification)

Separation of MixturesSeparation of Mixtures

Separating FunnelSeparating FunnelTo separate two To separate two

immiscible liquids and immiscible liquids and for solvent extraction for solvent extraction This technique makes This technique makes use of a difference in use of a difference in densitiesdensities

Separation by solubilitySeparation by solubilityTo separate mixtures of To separate mixtures of

solidssolids One solid is soluble in One solid is soluble in

a solvent and the a solvent and the others are notothers are not

The insoluble The insoluble components are components are removed by filtrationremoved by filtration

Evaporation is used to Evaporation is used to recover the pure recover the pure dissolved substance dissolved substance (solute)(solute)

Separation of MixturesSeparation of MixturesLiquification and Liquification and

fractional distillationfractional distillationTo separate mixtures of To separate mixtures of

gases-gases are cooled gases-gases are cooled to liquefy them to liquefy them followed by fractional followed by fractional distillation Fractional distillation Fractional distillation allows for distillation allows for separation of separation of substances with similar substances with similar boiling points boiling points

Other methods to Other methods to separate gases would separate gases would make use of differences make use of differences in solubility in liquids in solubility in liquids such as watersuch as water

Separation of MixturesSeparation of Mixtures

ChromatographyChromatography is the separation of mixtures by selective adsorption is the separation of mixtures by selective adsorption

(absorbing onto the surface) onto a (absorbing onto the surface) onto a stationary phasestationary phase This This technique is used to sort a mixture out into its separate technique is used to sort a mixture out into its separate componentscomponents

There are several types for various mixtures and they There are several types for various mixtures and they includeinclude

Column chromatography Column chromatography Paper chromatographyPaper chromatography Thin layer chromatographyThin layer chromatography Gas chromatography (GC)Gas chromatography (GC)

All techniques make use of an inert substance such as All techniques make use of an inert substance such as alumina silica or paper The components of a mixture alumina silica or paper The components of a mixture adhere to the inert substance with different strengths adhere to the inert substance with different strengths which leads to separation which leads to separation

Separation of MixturesSeparation of MixturesPaper chromatographyPaper chromatography This is the simplest form of This is the simplest form of

chromatography chromatography The stationary phase is a special The stationary phase is a special

chromatography paper but often filter chromatography paper but often filter paper is used in schools paper is used in schools

The mobile phase is a solvent mixture eg The mobile phase is a solvent mixture eg water and ethanol water and ethanol

The mixture under analysis is placed in a The mixture under analysis is placed in a tiny concentrated dot near the bottom of tiny concentrated dot near the bottom of the paper the paper

The paper is hung with the bottom dipped The paper is hung with the bottom dipped in solvent which rises up the paper to come in solvent which rises up the paper to come in contact with the mixture in contact with the mixture

As the solvent rises further up the paper As the solvent rises further up the paper the components are separated as they are the components are separated as they are swept along swept along

The strip of paper is called a The strip of paper is called a chromatogramchromatogram Identification of the components is based on Identification of the components is based on

RRf values ndash a ratio between the distance f values ndash a ratio between the distance travelled by the component to the distance travelled by the component to the distance travelled by the travelled by the solvent frontsolvent front

Starting line

Solvent Front

Separation of MixturesSeparation of MixturesGas chromatography (GC) Gas chromatography (GC) uses a stationary phase and a uses a stationary phase and a

mobile phase The mobile phase is a mobile phase The mobile phase is a carrier gascarrier gas and the and the stationary phase may be a liquid or a solid GC is a very stationary phase may be a liquid or a solid GC is a very rapid highly sensitive and reliable form of analysis but is rapid highly sensitive and reliable form of analysis but is limited to compounds that can be vaporised without limited to compounds that can be vaporised without decomposing Low-molecular-weight organic compounds decomposing Low-molecular-weight organic compounds are ideal for this sort of analysis The diagram on the right are ideal for this sort of analysis The diagram on the right shows a typical chromatogramshows a typical chromatogram

Separation of Mixtures-summary of Separation of Mixtures-summary of techniquestechniques

Separation MethodSeparation Method Property used to Property used to achieve separationachieve separation

SievingSieving Particle sizeParticle size

FiltrationFiltration One substance is solid the One substance is solid the other is liquid or solutionother is liquid or solution

EvaporationEvaporation Liquid has a much lower Liquid has a much lower boiling point than the solidboiling point than the solid

DistillationDistillation Large difference in boiling Large difference in boiling pointpoint

Fractional DistillationFractional Distillation Smaller difference in boiling Smaller difference in boiling pointpoint

Separating FunnelSeparating Funnel Density (mvol) of immiscible Density (mvol) of immiscible liquidsliquids

Adding a solvent then filtrationAdding a solvent then filtration One substance is soluble in a One substance is soluble in a solvent and the others are notsolvent and the others are not

ChromatographyChromatography Different adsorption to a Different adsorption to a stationary phasestationary phase

Separation of Mixtures-examplesSeparation of Mixtures-examples

Separation MethodSeparation Method Example of useExample of useSievingSieving To separate sand from gravel at a To separate sand from gravel at a

rock quarryrock quarry

FiltrationFiltration Drinking water purification Drinking water purification processesprocesses

EvaporationEvaporation Salt evaporation ponds for table saltSalt evaporation ponds for table salt

DistillationDistillation Obtaining pure water from sea Obtaining pure water from sea waterwater

Fractional DistillationFractional Distillation Separation of crude oil components Separation of crude oil components (petrol diesel kerosene waxes (petrol diesel kerosene waxes etc)etc)

Separating FunnelSeparating Funnel To remove oil from water solvent To remove oil from water solvent extraction in analytical testing (eg extraction in analytical testing (eg pesticides)pesticides)

Adding a solvent then filtrationAdding a solvent then filtration Removal of salt from sand with Removal of salt from sand with waterwater

ChromatographyChromatography Analytical testing (eg water Analytical testing (eg water contaminants)contaminants)

Chemical AnalysisChemical Analysis

TwoTwo general types general types

11 QualitativeQualitative AnalysisAnalysis to determine what substances are present to determine what substances are present

in a samplein a sample

22 QuantitativeQuantitative AnalysisAnalysis to determine how much of each substance to determine how much of each substance

there is in a samplethere is in a sample

Percentage compositionPercentage composition

Quantitative Analysis of a substance involves Quantitative Analysis of a substance involves the determination of actual percentages the determination of actual percentages present in a sample present in a sample

This involves eitherThis involves either11 VolumetricVolumetric analysis-involves measuring analysis-involves measuring

percentages by volumepercentages by volume22 GravimetricGravimetric analysis-involves measuring analysis-involves measuring

percentages by massweightpercentages by massweight

In either case the calculations will be similarIn either case the calculations will be similar

Gravimetric AnalysisGravimetric Analysis

There are a variety of reasons for determining the There are a variety of reasons for determining the composition of a substance in a mixture includingcomposition of a substance in a mixture including

Determining the amount of pollutants present in Determining the amount of pollutants present in drinking waterdrinking water

Determining the amount of a metal present in an Determining the amount of a metal present in an ore sampleore sample

Quality control in the production of a variety of Quality control in the production of a variety of consumer goods (eg ensuring the correct consumer goods (eg ensuring the correct quantities of N P and K in fertilisers) quantities of N P and K in fertilisers)

Soil testing to determine suitability for plantcrop Soil testing to determine suitability for plantcrop growthgrowth

Gravimetric AnalysisGravimetric AnalysisGravimetric analysis involves the use of a variety of Gravimetric analysis involves the use of a variety of

separation techniques followed by a simple calculation to separation techniques followed by a simple calculation to determine the percentage composition of a substancedetermine the percentage composition of a substance

For exampleFor exampleA sample of ore weighing 1063g is found to contain 155g of A sample of ore weighing 1063g is found to contain 155g of

nickel (Ni) and 076g of cobalt (Co) Calculate the nickel (Ni) and 076g of cobalt (Co) Calculate the composition of Ni and Cocomposition of Ni and Co

component = component = mass of component in samplemass of component in sample x 100 x 100 total mass of sampletotal mass of sample

NiNi = 155g1063g x 100 = = 155g1063g x 100 = 14581458

CoCo = 076g1063g x 100 = = 076g1063g x 100 = 715715

Class AssignmentClass Assignment

Choose a mixture from one of the 4 spheres of the Earth and gather Choose a mixture from one of the 4 spheres of the Earth and gather information about the followinginformation about the following

Industrial separation processes to separate the mixtureIndustrial separation processes to separate the mixture The properties of the mixture that are used in these separation The properties of the mixture that are used in these separation

processesprocesses The products of separation and their usesThe products of separation and their uses The issues associated with wastes generated from these The issues associated with wastes generated from these

processesprocesses

Present your information in Report Style with supporting diagrams Present your information in Report Style with supporting diagrams and a source list and a source list

82 The Chemical Earth82 The Chemical Earth

Focus 2Focus 2Although most elements are found in Although most elements are found in

combinations on Earth some elements are combinations on Earth some elements are found uncombinedfound uncombined

Properties of the Properties of the ElementsElements

Elements are classified into three categories based on their Elements are classified into three categories based on their physical propertiesphysical properties

The 3 categories areThe 3 categories are

MetalsMetals Non-metalsNon-metals Semi-metals or metaloidsSemi-metals or metaloids

Some of the physical properties used in this classificationSome of the physical properties used in this classification

Density (massvolume)Density (massvolume) Boiling pointmelting pointBoiling pointmelting point Electrical and Thermal conductivityElectrical and Thermal conductivity State at room temperature (solid liquid or gas)State at room temperature (solid liquid or gas) AppearanceAppearance

The Periodic TableThe Periodic Table

httplibrarytedankarak12trchemistryvol1atomstrtrans50jpg

Separation of MixturesSeparation of Mixtures

Separating FunnelSeparating FunnelTo separate two To separate two

immiscible liquids and immiscible liquids and for solvent extraction for solvent extraction This technique makes This technique makes use of a difference in use of a difference in densitiesdensities

Separation by solubilitySeparation by solubilityTo separate mixtures of To separate mixtures of

solidssolids One solid is soluble in One solid is soluble in

a solvent and the a solvent and the others are notothers are not

The insoluble The insoluble components are components are removed by filtrationremoved by filtration

Evaporation is used to Evaporation is used to recover the pure recover the pure dissolved substance dissolved substance (solute)(solute)

Separation of MixturesSeparation of MixturesLiquification and Liquification and

fractional distillationfractional distillationTo separate mixtures of To separate mixtures of

gases-gases are cooled gases-gases are cooled to liquefy them to liquefy them followed by fractional followed by fractional distillation Fractional distillation Fractional distillation allows for distillation allows for separation of separation of substances with similar substances with similar boiling points boiling points

Other methods to Other methods to separate gases would separate gases would make use of differences make use of differences in solubility in liquids in solubility in liquids such as watersuch as water

Separation of MixturesSeparation of Mixtures

ChromatographyChromatography is the separation of mixtures by selective adsorption is the separation of mixtures by selective adsorption

(absorbing onto the surface) onto a (absorbing onto the surface) onto a stationary phasestationary phase This This technique is used to sort a mixture out into its separate technique is used to sort a mixture out into its separate componentscomponents

There are several types for various mixtures and they There are several types for various mixtures and they includeinclude

Column chromatography Column chromatography Paper chromatographyPaper chromatography Thin layer chromatographyThin layer chromatography Gas chromatography (GC)Gas chromatography (GC)

All techniques make use of an inert substance such as All techniques make use of an inert substance such as alumina silica or paper The components of a mixture alumina silica or paper The components of a mixture adhere to the inert substance with different strengths adhere to the inert substance with different strengths which leads to separation which leads to separation

Separation of MixturesSeparation of MixturesPaper chromatographyPaper chromatography This is the simplest form of This is the simplest form of

chromatography chromatography The stationary phase is a special The stationary phase is a special

chromatography paper but often filter chromatography paper but often filter paper is used in schools paper is used in schools

The mobile phase is a solvent mixture eg The mobile phase is a solvent mixture eg water and ethanol water and ethanol

The mixture under analysis is placed in a The mixture under analysis is placed in a tiny concentrated dot near the bottom of tiny concentrated dot near the bottom of the paper the paper

The paper is hung with the bottom dipped The paper is hung with the bottom dipped in solvent which rises up the paper to come in solvent which rises up the paper to come in contact with the mixture in contact with the mixture

As the solvent rises further up the paper As the solvent rises further up the paper the components are separated as they are the components are separated as they are swept along swept along

The strip of paper is called a The strip of paper is called a chromatogramchromatogram Identification of the components is based on Identification of the components is based on

RRf values ndash a ratio between the distance f values ndash a ratio between the distance travelled by the component to the distance travelled by the component to the distance travelled by the travelled by the solvent frontsolvent front

Starting line

Solvent Front

Separation of MixturesSeparation of MixturesGas chromatography (GC) Gas chromatography (GC) uses a stationary phase and a uses a stationary phase and a

mobile phase The mobile phase is a mobile phase The mobile phase is a carrier gascarrier gas and the and the stationary phase may be a liquid or a solid GC is a very stationary phase may be a liquid or a solid GC is a very rapid highly sensitive and reliable form of analysis but is rapid highly sensitive and reliable form of analysis but is limited to compounds that can be vaporised without limited to compounds that can be vaporised without decomposing Low-molecular-weight organic compounds decomposing Low-molecular-weight organic compounds are ideal for this sort of analysis The diagram on the right are ideal for this sort of analysis The diagram on the right shows a typical chromatogramshows a typical chromatogram

Separation of Mixtures-summary of Separation of Mixtures-summary of techniquestechniques

Separation MethodSeparation Method Property used to Property used to achieve separationachieve separation

SievingSieving Particle sizeParticle size

FiltrationFiltration One substance is solid the One substance is solid the other is liquid or solutionother is liquid or solution

EvaporationEvaporation Liquid has a much lower Liquid has a much lower boiling point than the solidboiling point than the solid

DistillationDistillation Large difference in boiling Large difference in boiling pointpoint

Fractional DistillationFractional Distillation Smaller difference in boiling Smaller difference in boiling pointpoint

Separating FunnelSeparating Funnel Density (mvol) of immiscible Density (mvol) of immiscible liquidsliquids

Adding a solvent then filtrationAdding a solvent then filtration One substance is soluble in a One substance is soluble in a solvent and the others are notsolvent and the others are not

ChromatographyChromatography Different adsorption to a Different adsorption to a stationary phasestationary phase

Separation of Mixtures-examplesSeparation of Mixtures-examples

Separation MethodSeparation Method Example of useExample of useSievingSieving To separate sand from gravel at a To separate sand from gravel at a

rock quarryrock quarry

FiltrationFiltration Drinking water purification Drinking water purification processesprocesses

EvaporationEvaporation Salt evaporation ponds for table saltSalt evaporation ponds for table salt

DistillationDistillation Obtaining pure water from sea Obtaining pure water from sea waterwater

Fractional DistillationFractional Distillation Separation of crude oil components Separation of crude oil components (petrol diesel kerosene waxes (petrol diesel kerosene waxes etc)etc)

Separating FunnelSeparating Funnel To remove oil from water solvent To remove oil from water solvent extraction in analytical testing (eg extraction in analytical testing (eg pesticides)pesticides)

Adding a solvent then filtrationAdding a solvent then filtration Removal of salt from sand with Removal of salt from sand with waterwater

ChromatographyChromatography Analytical testing (eg water Analytical testing (eg water contaminants)contaminants)

Chemical AnalysisChemical Analysis

TwoTwo general types general types

11 QualitativeQualitative AnalysisAnalysis to determine what substances are present to determine what substances are present

in a samplein a sample

22 QuantitativeQuantitative AnalysisAnalysis to determine how much of each substance to determine how much of each substance

there is in a samplethere is in a sample

Percentage compositionPercentage composition

Quantitative Analysis of a substance involves Quantitative Analysis of a substance involves the determination of actual percentages the determination of actual percentages present in a sample present in a sample

This involves eitherThis involves either11 VolumetricVolumetric analysis-involves measuring analysis-involves measuring

percentages by volumepercentages by volume22 GravimetricGravimetric analysis-involves measuring analysis-involves measuring

percentages by massweightpercentages by massweight

In either case the calculations will be similarIn either case the calculations will be similar

Gravimetric AnalysisGravimetric Analysis

There are a variety of reasons for determining the There are a variety of reasons for determining the composition of a substance in a mixture includingcomposition of a substance in a mixture including

Determining the amount of pollutants present in Determining the amount of pollutants present in drinking waterdrinking water

Determining the amount of a metal present in an Determining the amount of a metal present in an ore sampleore sample

Quality control in the production of a variety of Quality control in the production of a variety of consumer goods (eg ensuring the correct consumer goods (eg ensuring the correct quantities of N P and K in fertilisers) quantities of N P and K in fertilisers)

Soil testing to determine suitability for plantcrop Soil testing to determine suitability for plantcrop growthgrowth

Gravimetric AnalysisGravimetric AnalysisGravimetric analysis involves the use of a variety of Gravimetric analysis involves the use of a variety of

separation techniques followed by a simple calculation to separation techniques followed by a simple calculation to determine the percentage composition of a substancedetermine the percentage composition of a substance

For exampleFor exampleA sample of ore weighing 1063g is found to contain 155g of A sample of ore weighing 1063g is found to contain 155g of

nickel (Ni) and 076g of cobalt (Co) Calculate the nickel (Ni) and 076g of cobalt (Co) Calculate the composition of Ni and Cocomposition of Ni and Co

component = component = mass of component in samplemass of component in sample x 100 x 100 total mass of sampletotal mass of sample

NiNi = 155g1063g x 100 = = 155g1063g x 100 = 14581458

CoCo = 076g1063g x 100 = = 076g1063g x 100 = 715715

Class AssignmentClass Assignment

Choose a mixture from one of the 4 spheres of the Earth and gather Choose a mixture from one of the 4 spheres of the Earth and gather information about the followinginformation about the following

Industrial separation processes to separate the mixtureIndustrial separation processes to separate the mixture The properties of the mixture that are used in these separation The properties of the mixture that are used in these separation

processesprocesses The products of separation and their usesThe products of separation and their uses The issues associated with wastes generated from these The issues associated with wastes generated from these

processesprocesses

Present your information in Report Style with supporting diagrams Present your information in Report Style with supporting diagrams and a source list and a source list

82 The Chemical Earth82 The Chemical Earth

Focus 2Focus 2Although most elements are found in Although most elements are found in

combinations on Earth some elements are combinations on Earth some elements are found uncombinedfound uncombined

Properties of the Properties of the ElementsElements

Elements are classified into three categories based on their Elements are classified into three categories based on their physical propertiesphysical properties

The 3 categories areThe 3 categories are

MetalsMetals Non-metalsNon-metals Semi-metals or metaloidsSemi-metals or metaloids

Some of the physical properties used in this classificationSome of the physical properties used in this classification

Density (massvolume)Density (massvolume) Boiling pointmelting pointBoiling pointmelting point Electrical and Thermal conductivityElectrical and Thermal conductivity State at room temperature (solid liquid or gas)State at room temperature (solid liquid or gas) AppearanceAppearance

The Periodic TableThe Periodic Table

httplibrarytedankarak12trchemistryvol1atomstrtrans50jpg

Separation of MixturesSeparation of MixturesLiquification and Liquification and

fractional distillationfractional distillationTo separate mixtures of To separate mixtures of

gases-gases are cooled gases-gases are cooled to liquefy them to liquefy them followed by fractional followed by fractional distillation Fractional distillation Fractional distillation allows for distillation allows for separation of separation of substances with similar substances with similar boiling points boiling points

Other methods to Other methods to separate gases would separate gases would make use of differences make use of differences in solubility in liquids in solubility in liquids such as watersuch as water

Separation of MixturesSeparation of Mixtures

ChromatographyChromatography is the separation of mixtures by selective adsorption is the separation of mixtures by selective adsorption

(absorbing onto the surface) onto a (absorbing onto the surface) onto a stationary phasestationary phase This This technique is used to sort a mixture out into its separate technique is used to sort a mixture out into its separate componentscomponents

There are several types for various mixtures and they There are several types for various mixtures and they includeinclude

Column chromatography Column chromatography Paper chromatographyPaper chromatography Thin layer chromatographyThin layer chromatography Gas chromatography (GC)Gas chromatography (GC)

All techniques make use of an inert substance such as All techniques make use of an inert substance such as alumina silica or paper The components of a mixture alumina silica or paper The components of a mixture adhere to the inert substance with different strengths adhere to the inert substance with different strengths which leads to separation which leads to separation

Separation of MixturesSeparation of MixturesPaper chromatographyPaper chromatography This is the simplest form of This is the simplest form of

chromatography chromatography The stationary phase is a special The stationary phase is a special

chromatography paper but often filter chromatography paper but often filter paper is used in schools paper is used in schools

The mobile phase is a solvent mixture eg The mobile phase is a solvent mixture eg water and ethanol water and ethanol

The mixture under analysis is placed in a The mixture under analysis is placed in a tiny concentrated dot near the bottom of tiny concentrated dot near the bottom of the paper the paper

The paper is hung with the bottom dipped The paper is hung with the bottom dipped in solvent which rises up the paper to come in solvent which rises up the paper to come in contact with the mixture in contact with the mixture

As the solvent rises further up the paper As the solvent rises further up the paper the components are separated as they are the components are separated as they are swept along swept along

The strip of paper is called a The strip of paper is called a chromatogramchromatogram Identification of the components is based on Identification of the components is based on

RRf values ndash a ratio between the distance f values ndash a ratio between the distance travelled by the component to the distance travelled by the component to the distance travelled by the travelled by the solvent frontsolvent front

Starting line

Solvent Front

Separation of MixturesSeparation of MixturesGas chromatography (GC) Gas chromatography (GC) uses a stationary phase and a uses a stationary phase and a

mobile phase The mobile phase is a mobile phase The mobile phase is a carrier gascarrier gas and the and the stationary phase may be a liquid or a solid GC is a very stationary phase may be a liquid or a solid GC is a very rapid highly sensitive and reliable form of analysis but is rapid highly sensitive and reliable form of analysis but is limited to compounds that can be vaporised without limited to compounds that can be vaporised without decomposing Low-molecular-weight organic compounds decomposing Low-molecular-weight organic compounds are ideal for this sort of analysis The diagram on the right are ideal for this sort of analysis The diagram on the right shows a typical chromatogramshows a typical chromatogram

Separation of Mixtures-summary of Separation of Mixtures-summary of techniquestechniques

Separation MethodSeparation Method Property used to Property used to achieve separationachieve separation

SievingSieving Particle sizeParticle size

FiltrationFiltration One substance is solid the One substance is solid the other is liquid or solutionother is liquid or solution

EvaporationEvaporation Liquid has a much lower Liquid has a much lower boiling point than the solidboiling point than the solid

DistillationDistillation Large difference in boiling Large difference in boiling pointpoint

Fractional DistillationFractional Distillation Smaller difference in boiling Smaller difference in boiling pointpoint

Separating FunnelSeparating Funnel Density (mvol) of immiscible Density (mvol) of immiscible liquidsliquids

Adding a solvent then filtrationAdding a solvent then filtration One substance is soluble in a One substance is soluble in a solvent and the others are notsolvent and the others are not

ChromatographyChromatography Different adsorption to a Different adsorption to a stationary phasestationary phase

Separation of Mixtures-examplesSeparation of Mixtures-examples

Separation MethodSeparation Method Example of useExample of useSievingSieving To separate sand from gravel at a To separate sand from gravel at a

rock quarryrock quarry

FiltrationFiltration Drinking water purification Drinking water purification processesprocesses

EvaporationEvaporation Salt evaporation ponds for table saltSalt evaporation ponds for table salt

DistillationDistillation Obtaining pure water from sea Obtaining pure water from sea waterwater

Fractional DistillationFractional Distillation Separation of crude oil components Separation of crude oil components (petrol diesel kerosene waxes (petrol diesel kerosene waxes etc)etc)

Separating FunnelSeparating Funnel To remove oil from water solvent To remove oil from water solvent extraction in analytical testing (eg extraction in analytical testing (eg pesticides)pesticides)

Adding a solvent then filtrationAdding a solvent then filtration Removal of salt from sand with Removal of salt from sand with waterwater

ChromatographyChromatography Analytical testing (eg water Analytical testing (eg water contaminants)contaminants)

Chemical AnalysisChemical Analysis

TwoTwo general types general types

11 QualitativeQualitative AnalysisAnalysis to determine what substances are present to determine what substances are present

in a samplein a sample

22 QuantitativeQuantitative AnalysisAnalysis to determine how much of each substance to determine how much of each substance

there is in a samplethere is in a sample

Percentage compositionPercentage composition

Quantitative Analysis of a substance involves Quantitative Analysis of a substance involves the determination of actual percentages the determination of actual percentages present in a sample present in a sample

This involves eitherThis involves either11 VolumetricVolumetric analysis-involves measuring analysis-involves measuring

percentages by volumepercentages by volume22 GravimetricGravimetric analysis-involves measuring analysis-involves measuring

percentages by massweightpercentages by massweight

In either case the calculations will be similarIn either case the calculations will be similar

Gravimetric AnalysisGravimetric Analysis

There are a variety of reasons for determining the There are a variety of reasons for determining the composition of a substance in a mixture includingcomposition of a substance in a mixture including

Determining the amount of pollutants present in Determining the amount of pollutants present in drinking waterdrinking water

Determining the amount of a metal present in an Determining the amount of a metal present in an ore sampleore sample

Quality control in the production of a variety of Quality control in the production of a variety of consumer goods (eg ensuring the correct consumer goods (eg ensuring the correct quantities of N P and K in fertilisers) quantities of N P and K in fertilisers)

Soil testing to determine suitability for plantcrop Soil testing to determine suitability for plantcrop growthgrowth

Gravimetric AnalysisGravimetric AnalysisGravimetric analysis involves the use of a variety of Gravimetric analysis involves the use of a variety of

separation techniques followed by a simple calculation to separation techniques followed by a simple calculation to determine the percentage composition of a substancedetermine the percentage composition of a substance

For exampleFor exampleA sample of ore weighing 1063g is found to contain 155g of A sample of ore weighing 1063g is found to contain 155g of

nickel (Ni) and 076g of cobalt (Co) Calculate the nickel (Ni) and 076g of cobalt (Co) Calculate the composition of Ni and Cocomposition of Ni and Co

component = component = mass of component in samplemass of component in sample x 100 x 100 total mass of sampletotal mass of sample

NiNi = 155g1063g x 100 = = 155g1063g x 100 = 14581458

CoCo = 076g1063g x 100 = = 076g1063g x 100 = 715715

Class AssignmentClass Assignment

Choose a mixture from one of the 4 spheres of the Earth and gather Choose a mixture from one of the 4 spheres of the Earth and gather information about the followinginformation about the following

Industrial separation processes to separate the mixtureIndustrial separation processes to separate the mixture The properties of the mixture that are used in these separation The properties of the mixture that are used in these separation

processesprocesses The products of separation and their usesThe products of separation and their uses The issues associated with wastes generated from these The issues associated with wastes generated from these

processesprocesses

Present your information in Report Style with supporting diagrams Present your information in Report Style with supporting diagrams and a source list and a source list

82 The Chemical Earth82 The Chemical Earth

Focus 2Focus 2Although most elements are found in Although most elements are found in

combinations on Earth some elements are combinations on Earth some elements are found uncombinedfound uncombined

Properties of the Properties of the ElementsElements

Elements are classified into three categories based on their Elements are classified into three categories based on their physical propertiesphysical properties

The 3 categories areThe 3 categories are

MetalsMetals Non-metalsNon-metals Semi-metals or metaloidsSemi-metals or metaloids

Some of the physical properties used in this classificationSome of the physical properties used in this classification

Density (massvolume)Density (massvolume) Boiling pointmelting pointBoiling pointmelting point Electrical and Thermal conductivityElectrical and Thermal conductivity State at room temperature (solid liquid or gas)State at room temperature (solid liquid or gas) AppearanceAppearance

The Periodic TableThe Periodic Table

httplibrarytedankarak12trchemistryvol1atomstrtrans50jpg

Separation of MixturesSeparation of Mixtures

ChromatographyChromatography is the separation of mixtures by selective adsorption is the separation of mixtures by selective adsorption

(absorbing onto the surface) onto a (absorbing onto the surface) onto a stationary phasestationary phase This This technique is used to sort a mixture out into its separate technique is used to sort a mixture out into its separate componentscomponents

There are several types for various mixtures and they There are several types for various mixtures and they includeinclude

Column chromatography Column chromatography Paper chromatographyPaper chromatography Thin layer chromatographyThin layer chromatography Gas chromatography (GC)Gas chromatography (GC)

All techniques make use of an inert substance such as All techniques make use of an inert substance such as alumina silica or paper The components of a mixture alumina silica or paper The components of a mixture adhere to the inert substance with different strengths adhere to the inert substance with different strengths which leads to separation which leads to separation

Separation of MixturesSeparation of MixturesPaper chromatographyPaper chromatography This is the simplest form of This is the simplest form of

chromatography chromatography The stationary phase is a special The stationary phase is a special

chromatography paper but often filter chromatography paper but often filter paper is used in schools paper is used in schools

The mobile phase is a solvent mixture eg The mobile phase is a solvent mixture eg water and ethanol water and ethanol

The mixture under analysis is placed in a The mixture under analysis is placed in a tiny concentrated dot near the bottom of tiny concentrated dot near the bottom of the paper the paper

The paper is hung with the bottom dipped The paper is hung with the bottom dipped in solvent which rises up the paper to come in solvent which rises up the paper to come in contact with the mixture in contact with the mixture

As the solvent rises further up the paper As the solvent rises further up the paper the components are separated as they are the components are separated as they are swept along swept along

The strip of paper is called a The strip of paper is called a chromatogramchromatogram Identification of the components is based on Identification of the components is based on

RRf values ndash a ratio between the distance f values ndash a ratio between the distance travelled by the component to the distance travelled by the component to the distance travelled by the travelled by the solvent frontsolvent front

Starting line

Solvent Front

Separation of MixturesSeparation of MixturesGas chromatography (GC) Gas chromatography (GC) uses a stationary phase and a uses a stationary phase and a

mobile phase The mobile phase is a mobile phase The mobile phase is a carrier gascarrier gas and the and the stationary phase may be a liquid or a solid GC is a very stationary phase may be a liquid or a solid GC is a very rapid highly sensitive and reliable form of analysis but is rapid highly sensitive and reliable form of analysis but is limited to compounds that can be vaporised without limited to compounds that can be vaporised without decomposing Low-molecular-weight organic compounds decomposing Low-molecular-weight organic compounds are ideal for this sort of analysis The diagram on the right are ideal for this sort of analysis The diagram on the right shows a typical chromatogramshows a typical chromatogram

Separation of Mixtures-summary of Separation of Mixtures-summary of techniquestechniques

Separation MethodSeparation Method Property used to Property used to achieve separationachieve separation

SievingSieving Particle sizeParticle size

FiltrationFiltration One substance is solid the One substance is solid the other is liquid or solutionother is liquid or solution

EvaporationEvaporation Liquid has a much lower Liquid has a much lower boiling point than the solidboiling point than the solid

DistillationDistillation Large difference in boiling Large difference in boiling pointpoint

Fractional DistillationFractional Distillation Smaller difference in boiling Smaller difference in boiling pointpoint

Separating FunnelSeparating Funnel Density (mvol) of immiscible Density (mvol) of immiscible liquidsliquids

Adding a solvent then filtrationAdding a solvent then filtration One substance is soluble in a One substance is soluble in a solvent and the others are notsolvent and the others are not

ChromatographyChromatography Different adsorption to a Different adsorption to a stationary phasestationary phase

Separation of Mixtures-examplesSeparation of Mixtures-examples

Separation MethodSeparation Method Example of useExample of useSievingSieving To separate sand from gravel at a To separate sand from gravel at a

rock quarryrock quarry

FiltrationFiltration Drinking water purification Drinking water purification processesprocesses

EvaporationEvaporation Salt evaporation ponds for table saltSalt evaporation ponds for table salt

DistillationDistillation Obtaining pure water from sea Obtaining pure water from sea waterwater

Fractional DistillationFractional Distillation Separation of crude oil components Separation of crude oil components (petrol diesel kerosene waxes (petrol diesel kerosene waxes etc)etc)

Separating FunnelSeparating Funnel To remove oil from water solvent To remove oil from water solvent extraction in analytical testing (eg extraction in analytical testing (eg pesticides)pesticides)

Adding a solvent then filtrationAdding a solvent then filtration Removal of salt from sand with Removal of salt from sand with waterwater

ChromatographyChromatography Analytical testing (eg water Analytical testing (eg water contaminants)contaminants)

Chemical AnalysisChemical Analysis

TwoTwo general types general types

11 QualitativeQualitative AnalysisAnalysis to determine what substances are present to determine what substances are present

in a samplein a sample

22 QuantitativeQuantitative AnalysisAnalysis to determine how much of each substance to determine how much of each substance

there is in a samplethere is in a sample

Percentage compositionPercentage composition

Quantitative Analysis of a substance involves Quantitative Analysis of a substance involves the determination of actual percentages the determination of actual percentages present in a sample present in a sample

This involves eitherThis involves either11 VolumetricVolumetric analysis-involves measuring analysis-involves measuring

percentages by volumepercentages by volume22 GravimetricGravimetric analysis-involves measuring analysis-involves measuring

percentages by massweightpercentages by massweight

In either case the calculations will be similarIn either case the calculations will be similar

Gravimetric AnalysisGravimetric Analysis

There are a variety of reasons for determining the There are a variety of reasons for determining the composition of a substance in a mixture includingcomposition of a substance in a mixture including

Determining the amount of pollutants present in Determining the amount of pollutants present in drinking waterdrinking water

Determining the amount of a metal present in an Determining the amount of a metal present in an ore sampleore sample

Quality control in the production of a variety of Quality control in the production of a variety of consumer goods (eg ensuring the correct consumer goods (eg ensuring the correct quantities of N P and K in fertilisers) quantities of N P and K in fertilisers)

Soil testing to determine suitability for plantcrop Soil testing to determine suitability for plantcrop growthgrowth

Gravimetric AnalysisGravimetric AnalysisGravimetric analysis involves the use of a variety of Gravimetric analysis involves the use of a variety of

separation techniques followed by a simple calculation to separation techniques followed by a simple calculation to determine the percentage composition of a substancedetermine the percentage composition of a substance

For exampleFor exampleA sample of ore weighing 1063g is found to contain 155g of A sample of ore weighing 1063g is found to contain 155g of

nickel (Ni) and 076g of cobalt (Co) Calculate the nickel (Ni) and 076g of cobalt (Co) Calculate the composition of Ni and Cocomposition of Ni and Co

component = component = mass of component in samplemass of component in sample x 100 x 100 total mass of sampletotal mass of sample

NiNi = 155g1063g x 100 = = 155g1063g x 100 = 14581458

CoCo = 076g1063g x 100 = = 076g1063g x 100 = 715715

Class AssignmentClass Assignment

Choose a mixture from one of the 4 spheres of the Earth and gather Choose a mixture from one of the 4 spheres of the Earth and gather information about the followinginformation about the following

Industrial separation processes to separate the mixtureIndustrial separation processes to separate the mixture The properties of the mixture that are used in these separation The properties of the mixture that are used in these separation

processesprocesses The products of separation and their usesThe products of separation and their uses The issues associated with wastes generated from these The issues associated with wastes generated from these

processesprocesses

Present your information in Report Style with supporting diagrams Present your information in Report Style with supporting diagrams and a source list and a source list

82 The Chemical Earth82 The Chemical Earth

Focus 2Focus 2Although most elements are found in Although most elements are found in

combinations on Earth some elements are combinations on Earth some elements are found uncombinedfound uncombined

Properties of the Properties of the ElementsElements

Elements are classified into three categories based on their Elements are classified into three categories based on their physical propertiesphysical properties

The 3 categories areThe 3 categories are

MetalsMetals Non-metalsNon-metals Semi-metals or metaloidsSemi-metals or metaloids

Some of the physical properties used in this classificationSome of the physical properties used in this classification

Density (massvolume)Density (massvolume) Boiling pointmelting pointBoiling pointmelting point Electrical and Thermal conductivityElectrical and Thermal conductivity State at room temperature (solid liquid or gas)State at room temperature (solid liquid or gas) AppearanceAppearance

The Periodic TableThe Periodic Table

httplibrarytedankarak12trchemistryvol1atomstrtrans50jpg

Separation of MixturesSeparation of MixturesPaper chromatographyPaper chromatography This is the simplest form of This is the simplest form of

chromatography chromatography The stationary phase is a special The stationary phase is a special

chromatography paper but often filter chromatography paper but often filter paper is used in schools paper is used in schools

The mobile phase is a solvent mixture eg The mobile phase is a solvent mixture eg water and ethanol water and ethanol

The mixture under analysis is placed in a The mixture under analysis is placed in a tiny concentrated dot near the bottom of tiny concentrated dot near the bottom of the paper the paper

The paper is hung with the bottom dipped The paper is hung with the bottom dipped in solvent which rises up the paper to come in solvent which rises up the paper to come in contact with the mixture in contact with the mixture

As the solvent rises further up the paper As the solvent rises further up the paper the components are separated as they are the components are separated as they are swept along swept along

The strip of paper is called a The strip of paper is called a chromatogramchromatogram Identification of the components is based on Identification of the components is based on

RRf values ndash a ratio between the distance f values ndash a ratio between the distance travelled by the component to the distance travelled by the component to the distance travelled by the travelled by the solvent frontsolvent front

Starting line

Solvent Front

Separation of MixturesSeparation of MixturesGas chromatography (GC) Gas chromatography (GC) uses a stationary phase and a uses a stationary phase and a

mobile phase The mobile phase is a mobile phase The mobile phase is a carrier gascarrier gas and the and the stationary phase may be a liquid or a solid GC is a very stationary phase may be a liquid or a solid GC is a very rapid highly sensitive and reliable form of analysis but is rapid highly sensitive and reliable form of analysis but is limited to compounds that can be vaporised without limited to compounds that can be vaporised without decomposing Low-molecular-weight organic compounds decomposing Low-molecular-weight organic compounds are ideal for this sort of analysis The diagram on the right are ideal for this sort of analysis The diagram on the right shows a typical chromatogramshows a typical chromatogram

Separation of Mixtures-summary of Separation of Mixtures-summary of techniquestechniques

Separation MethodSeparation Method Property used to Property used to achieve separationachieve separation

SievingSieving Particle sizeParticle size

FiltrationFiltration One substance is solid the One substance is solid the other is liquid or solutionother is liquid or solution

EvaporationEvaporation Liquid has a much lower Liquid has a much lower boiling point than the solidboiling point than the solid

DistillationDistillation Large difference in boiling Large difference in boiling pointpoint

Fractional DistillationFractional Distillation Smaller difference in boiling Smaller difference in boiling pointpoint

Separating FunnelSeparating Funnel Density (mvol) of immiscible Density (mvol) of immiscible liquidsliquids

Adding a solvent then filtrationAdding a solvent then filtration One substance is soluble in a One substance is soluble in a solvent and the others are notsolvent and the others are not

ChromatographyChromatography Different adsorption to a Different adsorption to a stationary phasestationary phase

Separation of Mixtures-examplesSeparation of Mixtures-examples

Separation MethodSeparation Method Example of useExample of useSievingSieving To separate sand from gravel at a To separate sand from gravel at a

rock quarryrock quarry

FiltrationFiltration Drinking water purification Drinking water purification processesprocesses

EvaporationEvaporation Salt evaporation ponds for table saltSalt evaporation ponds for table salt

DistillationDistillation Obtaining pure water from sea Obtaining pure water from sea waterwater

Fractional DistillationFractional Distillation Separation of crude oil components Separation of crude oil components (petrol diesel kerosene waxes (petrol diesel kerosene waxes etc)etc)

Separating FunnelSeparating Funnel To remove oil from water solvent To remove oil from water solvent extraction in analytical testing (eg extraction in analytical testing (eg pesticides)pesticides)

Adding a solvent then filtrationAdding a solvent then filtration Removal of salt from sand with Removal of salt from sand with waterwater

ChromatographyChromatography Analytical testing (eg water Analytical testing (eg water contaminants)contaminants)

Chemical AnalysisChemical Analysis

TwoTwo general types general types

11 QualitativeQualitative AnalysisAnalysis to determine what substances are present to determine what substances are present

in a samplein a sample

22 QuantitativeQuantitative AnalysisAnalysis to determine how much of each substance to determine how much of each substance

there is in a samplethere is in a sample

Percentage compositionPercentage composition

Quantitative Analysis of a substance involves Quantitative Analysis of a substance involves the determination of actual percentages the determination of actual percentages present in a sample present in a sample

This involves eitherThis involves either11 VolumetricVolumetric analysis-involves measuring analysis-involves measuring

percentages by volumepercentages by volume22 GravimetricGravimetric analysis-involves measuring analysis-involves measuring

percentages by massweightpercentages by massweight

In either case the calculations will be similarIn either case the calculations will be similar

Gravimetric AnalysisGravimetric Analysis

There are a variety of reasons for determining the There are a variety of reasons for determining the composition of a substance in a mixture includingcomposition of a substance in a mixture including

Determining the amount of pollutants present in Determining the amount of pollutants present in drinking waterdrinking water

Determining the amount of a metal present in an Determining the amount of a metal present in an ore sampleore sample

Quality control in the production of a variety of Quality control in the production of a variety of consumer goods (eg ensuring the correct consumer goods (eg ensuring the correct quantities of N P and K in fertilisers) quantities of N P and K in fertilisers)

Soil testing to determine suitability for plantcrop Soil testing to determine suitability for plantcrop growthgrowth

Gravimetric AnalysisGravimetric AnalysisGravimetric analysis involves the use of a variety of Gravimetric analysis involves the use of a variety of

separation techniques followed by a simple calculation to separation techniques followed by a simple calculation to determine the percentage composition of a substancedetermine the percentage composition of a substance

For exampleFor exampleA sample of ore weighing 1063g is found to contain 155g of A sample of ore weighing 1063g is found to contain 155g of

nickel (Ni) and 076g of cobalt (Co) Calculate the nickel (Ni) and 076g of cobalt (Co) Calculate the composition of Ni and Cocomposition of Ni and Co

component = component = mass of component in samplemass of component in sample x 100 x 100 total mass of sampletotal mass of sample

NiNi = 155g1063g x 100 = = 155g1063g x 100 = 14581458

CoCo = 076g1063g x 100 = = 076g1063g x 100 = 715715

Class AssignmentClass Assignment

Choose a mixture from one of the 4 spheres of the Earth and gather Choose a mixture from one of the 4 spheres of the Earth and gather information about the followinginformation about the following

Industrial separation processes to separate the mixtureIndustrial separation processes to separate the mixture The properties of the mixture that are used in these separation The properties of the mixture that are used in these separation

processesprocesses The products of separation and their usesThe products of separation and their uses The issues associated with wastes generated from these The issues associated with wastes generated from these

processesprocesses

Present your information in Report Style with supporting diagrams Present your information in Report Style with supporting diagrams and a source list and a source list

82 The Chemical Earth82 The Chemical Earth

Focus 2Focus 2Although most elements are found in Although most elements are found in

combinations on Earth some elements are combinations on Earth some elements are found uncombinedfound uncombined

Properties of the Properties of the ElementsElements

Elements are classified into three categories based on their Elements are classified into three categories based on their physical propertiesphysical properties

The 3 categories areThe 3 categories are

MetalsMetals Non-metalsNon-metals Semi-metals or metaloidsSemi-metals or metaloids

Some of the physical properties used in this classificationSome of the physical properties used in this classification

Density (massvolume)Density (massvolume) Boiling pointmelting pointBoiling pointmelting point Electrical and Thermal conductivityElectrical and Thermal conductivity State at room temperature (solid liquid or gas)State at room temperature (solid liquid or gas) AppearanceAppearance

The Periodic TableThe Periodic Table

httplibrarytedankarak12trchemistryvol1atomstrtrans50jpg

Separation of MixturesSeparation of MixturesGas chromatography (GC) Gas chromatography (GC) uses a stationary phase and a uses a stationary phase and a

mobile phase The mobile phase is a mobile phase The mobile phase is a carrier gascarrier gas and the and the stationary phase may be a liquid or a solid GC is a very stationary phase may be a liquid or a solid GC is a very rapid highly sensitive and reliable form of analysis but is rapid highly sensitive and reliable form of analysis but is limited to compounds that can be vaporised without limited to compounds that can be vaporised without decomposing Low-molecular-weight organic compounds decomposing Low-molecular-weight organic compounds are ideal for this sort of analysis The diagram on the right are ideal for this sort of analysis The diagram on the right shows a typical chromatogramshows a typical chromatogram

Separation of Mixtures-summary of Separation of Mixtures-summary of techniquestechniques

Separation MethodSeparation Method Property used to Property used to achieve separationachieve separation

SievingSieving Particle sizeParticle size

FiltrationFiltration One substance is solid the One substance is solid the other is liquid or solutionother is liquid or solution

EvaporationEvaporation Liquid has a much lower Liquid has a much lower boiling point than the solidboiling point than the solid

DistillationDistillation Large difference in boiling Large difference in boiling pointpoint

Fractional DistillationFractional Distillation Smaller difference in boiling Smaller difference in boiling pointpoint

Separating FunnelSeparating Funnel Density (mvol) of immiscible Density (mvol) of immiscible liquidsliquids

Adding a solvent then filtrationAdding a solvent then filtration One substance is soluble in a One substance is soluble in a solvent and the others are notsolvent and the others are not

ChromatographyChromatography Different adsorption to a Different adsorption to a stationary phasestationary phase

Separation of Mixtures-examplesSeparation of Mixtures-examples

Separation MethodSeparation Method Example of useExample of useSievingSieving To separate sand from gravel at a To separate sand from gravel at a

rock quarryrock quarry

FiltrationFiltration Drinking water purification Drinking water purification processesprocesses

EvaporationEvaporation Salt evaporation ponds for table saltSalt evaporation ponds for table salt

DistillationDistillation Obtaining pure water from sea Obtaining pure water from sea waterwater

Fractional DistillationFractional Distillation Separation of crude oil components Separation of crude oil components (petrol diesel kerosene waxes (petrol diesel kerosene waxes etc)etc)

Separating FunnelSeparating Funnel To remove oil from water solvent To remove oil from water solvent extraction in analytical testing (eg extraction in analytical testing (eg pesticides)pesticides)

Adding a solvent then filtrationAdding a solvent then filtration Removal of salt from sand with Removal of salt from sand with waterwater

ChromatographyChromatography Analytical testing (eg water Analytical testing (eg water contaminants)contaminants)

Chemical AnalysisChemical Analysis

TwoTwo general types general types

11 QualitativeQualitative AnalysisAnalysis to determine what substances are present to determine what substances are present

in a samplein a sample

22 QuantitativeQuantitative AnalysisAnalysis to determine how much of each substance to determine how much of each substance

there is in a samplethere is in a sample

Percentage compositionPercentage composition

Quantitative Analysis of a substance involves Quantitative Analysis of a substance involves the determination of actual percentages the determination of actual percentages present in a sample present in a sample

This involves eitherThis involves either11 VolumetricVolumetric analysis-involves measuring analysis-involves measuring

percentages by volumepercentages by volume22 GravimetricGravimetric analysis-involves measuring analysis-involves measuring

percentages by massweightpercentages by massweight

In either case the calculations will be similarIn either case the calculations will be similar

Gravimetric AnalysisGravimetric Analysis

There are a variety of reasons for determining the There are a variety of reasons for determining the composition of a substance in a mixture includingcomposition of a substance in a mixture including

Determining the amount of pollutants present in Determining the amount of pollutants present in drinking waterdrinking water

Determining the amount of a metal present in an Determining the amount of a metal present in an ore sampleore sample

Quality control in the production of a variety of Quality control in the production of a variety of consumer goods (eg ensuring the correct consumer goods (eg ensuring the correct quantities of N P and K in fertilisers) quantities of N P and K in fertilisers)

Soil testing to determine suitability for plantcrop Soil testing to determine suitability for plantcrop growthgrowth

Gravimetric AnalysisGravimetric AnalysisGravimetric analysis involves the use of a variety of Gravimetric analysis involves the use of a variety of

separation techniques followed by a simple calculation to separation techniques followed by a simple calculation to determine the percentage composition of a substancedetermine the percentage composition of a substance

For exampleFor exampleA sample of ore weighing 1063g is found to contain 155g of A sample of ore weighing 1063g is found to contain 155g of

nickel (Ni) and 076g of cobalt (Co) Calculate the nickel (Ni) and 076g of cobalt (Co) Calculate the composition of Ni and Cocomposition of Ni and Co

component = component = mass of component in samplemass of component in sample x 100 x 100 total mass of sampletotal mass of sample

NiNi = 155g1063g x 100 = = 155g1063g x 100 = 14581458

CoCo = 076g1063g x 100 = = 076g1063g x 100 = 715715

Class AssignmentClass Assignment

Choose a mixture from one of the 4 spheres of the Earth and gather Choose a mixture from one of the 4 spheres of the Earth and gather information about the followinginformation about the following

Industrial separation processes to separate the mixtureIndustrial separation processes to separate the mixture The properties of the mixture that are used in these separation The properties of the mixture that are used in these separation

processesprocesses The products of separation and their usesThe products of separation and their uses The issues associated with wastes generated from these The issues associated with wastes generated from these

processesprocesses

Present your information in Report Style with supporting diagrams Present your information in Report Style with supporting diagrams and a source list and a source list

82 The Chemical Earth82 The Chemical Earth

Focus 2Focus 2Although most elements are found in Although most elements are found in

combinations on Earth some elements are combinations on Earth some elements are found uncombinedfound uncombined

Properties of the Properties of the ElementsElements

Elements are classified into three categories based on their Elements are classified into three categories based on their physical propertiesphysical properties

The 3 categories areThe 3 categories are

MetalsMetals Non-metalsNon-metals Semi-metals or metaloidsSemi-metals or metaloids

Some of the physical properties used in this classificationSome of the physical properties used in this classification

Density (massvolume)Density (massvolume) Boiling pointmelting pointBoiling pointmelting point Electrical and Thermal conductivityElectrical and Thermal conductivity State at room temperature (solid liquid or gas)State at room temperature (solid liquid or gas) AppearanceAppearance

The Periodic TableThe Periodic Table

httplibrarytedankarak12trchemistryvol1atomstrtrans50jpg

Separation of Mixtures-summary of Separation of Mixtures-summary of techniquestechniques

Separation MethodSeparation Method Property used to Property used to achieve separationachieve separation

SievingSieving Particle sizeParticle size

FiltrationFiltration One substance is solid the One substance is solid the other is liquid or solutionother is liquid or solution

EvaporationEvaporation Liquid has a much lower Liquid has a much lower boiling point than the solidboiling point than the solid

DistillationDistillation Large difference in boiling Large difference in boiling pointpoint

Fractional DistillationFractional Distillation Smaller difference in boiling Smaller difference in boiling pointpoint

Separating FunnelSeparating Funnel Density (mvol) of immiscible Density (mvol) of immiscible liquidsliquids

Adding a solvent then filtrationAdding a solvent then filtration One substance is soluble in a One substance is soluble in a solvent and the others are notsolvent and the others are not

ChromatographyChromatography Different adsorption to a Different adsorption to a stationary phasestationary phase

Separation of Mixtures-examplesSeparation of Mixtures-examples

Separation MethodSeparation Method Example of useExample of useSievingSieving To separate sand from gravel at a To separate sand from gravel at a

rock quarryrock quarry

FiltrationFiltration Drinking water purification Drinking water purification processesprocesses

EvaporationEvaporation Salt evaporation ponds for table saltSalt evaporation ponds for table salt

DistillationDistillation Obtaining pure water from sea Obtaining pure water from sea waterwater

Fractional DistillationFractional Distillation Separation of crude oil components Separation of crude oil components (petrol diesel kerosene waxes (petrol diesel kerosene waxes etc)etc)

Separating FunnelSeparating Funnel To remove oil from water solvent To remove oil from water solvent extraction in analytical testing (eg extraction in analytical testing (eg pesticides)pesticides)

Adding a solvent then filtrationAdding a solvent then filtration Removal of salt from sand with Removal of salt from sand with waterwater

ChromatographyChromatography Analytical testing (eg water Analytical testing (eg water contaminants)contaminants)

Chemical AnalysisChemical Analysis

TwoTwo general types general types

11 QualitativeQualitative AnalysisAnalysis to determine what substances are present to determine what substances are present

in a samplein a sample

22 QuantitativeQuantitative AnalysisAnalysis to determine how much of each substance to determine how much of each substance

there is in a samplethere is in a sample

Percentage compositionPercentage composition

Quantitative Analysis of a substance involves Quantitative Analysis of a substance involves the determination of actual percentages the determination of actual percentages present in a sample present in a sample

This involves eitherThis involves either11 VolumetricVolumetric analysis-involves measuring analysis-involves measuring

percentages by volumepercentages by volume22 GravimetricGravimetric analysis-involves measuring analysis-involves measuring

percentages by massweightpercentages by massweight

In either case the calculations will be similarIn either case the calculations will be similar

Gravimetric AnalysisGravimetric Analysis

There are a variety of reasons for determining the There are a variety of reasons for determining the composition of a substance in a mixture includingcomposition of a substance in a mixture including

Determining the amount of pollutants present in Determining the amount of pollutants present in drinking waterdrinking water

Determining the amount of a metal present in an Determining the amount of a metal present in an ore sampleore sample

Quality control in the production of a variety of Quality control in the production of a variety of consumer goods (eg ensuring the correct consumer goods (eg ensuring the correct quantities of N P and K in fertilisers) quantities of N P and K in fertilisers)

Soil testing to determine suitability for plantcrop Soil testing to determine suitability for plantcrop growthgrowth

Gravimetric AnalysisGravimetric AnalysisGravimetric analysis involves the use of a variety of Gravimetric analysis involves the use of a variety of

separation techniques followed by a simple calculation to separation techniques followed by a simple calculation to determine the percentage composition of a substancedetermine the percentage composition of a substance

For exampleFor exampleA sample of ore weighing 1063g is found to contain 155g of A sample of ore weighing 1063g is found to contain 155g of

nickel (Ni) and 076g of cobalt (Co) Calculate the nickel (Ni) and 076g of cobalt (Co) Calculate the composition of Ni and Cocomposition of Ni and Co

component = component = mass of component in samplemass of component in sample x 100 x 100 total mass of sampletotal mass of sample

NiNi = 155g1063g x 100 = = 155g1063g x 100 = 14581458

CoCo = 076g1063g x 100 = = 076g1063g x 100 = 715715

Class AssignmentClass Assignment

Choose a mixture from one of the 4 spheres of the Earth and gather Choose a mixture from one of the 4 spheres of the Earth and gather information about the followinginformation about the following

Industrial separation processes to separate the mixtureIndustrial separation processes to separate the mixture The properties of the mixture that are used in these separation The properties of the mixture that are used in these separation

processesprocesses The products of separation and their usesThe products of separation and their uses The issues associated with wastes generated from these The issues associated with wastes generated from these

processesprocesses

Present your information in Report Style with supporting diagrams Present your information in Report Style with supporting diagrams and a source list and a source list

82 The Chemical Earth82 The Chemical Earth

Focus 2Focus 2Although most elements are found in Although most elements are found in

combinations on Earth some elements are combinations on Earth some elements are found uncombinedfound uncombined

Properties of the Properties of the ElementsElements

Elements are classified into three categories based on their Elements are classified into three categories based on their physical propertiesphysical properties

The 3 categories areThe 3 categories are

MetalsMetals Non-metalsNon-metals Semi-metals or metaloidsSemi-metals or metaloids

Some of the physical properties used in this classificationSome of the physical properties used in this classification

Density (massvolume)Density (massvolume) Boiling pointmelting pointBoiling pointmelting point Electrical and Thermal conductivityElectrical and Thermal conductivity State at room temperature (solid liquid or gas)State at room temperature (solid liquid or gas) AppearanceAppearance

The Periodic TableThe Periodic Table

httplibrarytedankarak12trchemistryvol1atomstrtrans50jpg

Separation of Mixtures-examplesSeparation of Mixtures-examples

Separation MethodSeparation Method Example of useExample of useSievingSieving To separate sand from gravel at a To separate sand from gravel at a

rock quarryrock quarry

FiltrationFiltration Drinking water purification Drinking water purification processesprocesses

EvaporationEvaporation Salt evaporation ponds for table saltSalt evaporation ponds for table salt

DistillationDistillation Obtaining pure water from sea Obtaining pure water from sea waterwater

Fractional DistillationFractional Distillation Separation of crude oil components Separation of crude oil components (petrol diesel kerosene waxes (petrol diesel kerosene waxes etc)etc)

Separating FunnelSeparating Funnel To remove oil from water solvent To remove oil from water solvent extraction in analytical testing (eg extraction in analytical testing (eg pesticides)pesticides)

Adding a solvent then filtrationAdding a solvent then filtration Removal of salt from sand with Removal of salt from sand with waterwater

ChromatographyChromatography Analytical testing (eg water Analytical testing (eg water contaminants)contaminants)

Chemical AnalysisChemical Analysis

TwoTwo general types general types

11 QualitativeQualitative AnalysisAnalysis to determine what substances are present to determine what substances are present

in a samplein a sample

22 QuantitativeQuantitative AnalysisAnalysis to determine how much of each substance to determine how much of each substance

there is in a samplethere is in a sample

Percentage compositionPercentage composition

Quantitative Analysis of a substance involves Quantitative Analysis of a substance involves the determination of actual percentages the determination of actual percentages present in a sample present in a sample

This involves eitherThis involves either11 VolumetricVolumetric analysis-involves measuring analysis-involves measuring

percentages by volumepercentages by volume22 GravimetricGravimetric analysis-involves measuring analysis-involves measuring

percentages by massweightpercentages by massweight

In either case the calculations will be similarIn either case the calculations will be similar

Gravimetric AnalysisGravimetric Analysis

There are a variety of reasons for determining the There are a variety of reasons for determining the composition of a substance in a mixture includingcomposition of a substance in a mixture including

Determining the amount of pollutants present in Determining the amount of pollutants present in drinking waterdrinking water

Determining the amount of a metal present in an Determining the amount of a metal present in an ore sampleore sample

Quality control in the production of a variety of Quality control in the production of a variety of consumer goods (eg ensuring the correct consumer goods (eg ensuring the correct quantities of N P and K in fertilisers) quantities of N P and K in fertilisers)

Soil testing to determine suitability for plantcrop Soil testing to determine suitability for plantcrop growthgrowth

Gravimetric AnalysisGravimetric AnalysisGravimetric analysis involves the use of a variety of Gravimetric analysis involves the use of a variety of

separation techniques followed by a simple calculation to separation techniques followed by a simple calculation to determine the percentage composition of a substancedetermine the percentage composition of a substance

For exampleFor exampleA sample of ore weighing 1063g is found to contain 155g of A sample of ore weighing 1063g is found to contain 155g of

nickel (Ni) and 076g of cobalt (Co) Calculate the nickel (Ni) and 076g of cobalt (Co) Calculate the composition of Ni and Cocomposition of Ni and Co

component = component = mass of component in samplemass of component in sample x 100 x 100 total mass of sampletotal mass of sample

NiNi = 155g1063g x 100 = = 155g1063g x 100 = 14581458

CoCo = 076g1063g x 100 = = 076g1063g x 100 = 715715

Class AssignmentClass Assignment

Choose a mixture from one of the 4 spheres of the Earth and gather Choose a mixture from one of the 4 spheres of the Earth and gather information about the followinginformation about the following

Industrial separation processes to separate the mixtureIndustrial separation processes to separate the mixture The properties of the mixture that are used in these separation The properties of the mixture that are used in these separation

processesprocesses The products of separation and their usesThe products of separation and their uses The issues associated with wastes generated from these The issues associated with wastes generated from these

processesprocesses

Present your information in Report Style with supporting diagrams Present your information in Report Style with supporting diagrams and a source list and a source list

82 The Chemical Earth82 The Chemical Earth

Focus 2Focus 2Although most elements are found in Although most elements are found in

combinations on Earth some elements are combinations on Earth some elements are found uncombinedfound uncombined

Properties of the Properties of the ElementsElements

Elements are classified into three categories based on their Elements are classified into three categories based on their physical propertiesphysical properties

The 3 categories areThe 3 categories are

MetalsMetals Non-metalsNon-metals Semi-metals or metaloidsSemi-metals or metaloids

Some of the physical properties used in this classificationSome of the physical properties used in this classification

Density (massvolume)Density (massvolume) Boiling pointmelting pointBoiling pointmelting point Electrical and Thermal conductivityElectrical and Thermal conductivity State at room temperature (solid liquid or gas)State at room temperature (solid liquid or gas) AppearanceAppearance

The Periodic TableThe Periodic Table

httplibrarytedankarak12trchemistryvol1atomstrtrans50jpg

Chemical AnalysisChemical Analysis

TwoTwo general types general types

11 QualitativeQualitative AnalysisAnalysis to determine what substances are present to determine what substances are present

in a samplein a sample

22 QuantitativeQuantitative AnalysisAnalysis to determine how much of each substance to determine how much of each substance

there is in a samplethere is in a sample

Percentage compositionPercentage composition

Quantitative Analysis of a substance involves Quantitative Analysis of a substance involves the determination of actual percentages the determination of actual percentages present in a sample present in a sample

This involves eitherThis involves either11 VolumetricVolumetric analysis-involves measuring analysis-involves measuring

percentages by volumepercentages by volume22 GravimetricGravimetric analysis-involves measuring analysis-involves measuring

percentages by massweightpercentages by massweight

In either case the calculations will be similarIn either case the calculations will be similar

Gravimetric AnalysisGravimetric Analysis

There are a variety of reasons for determining the There are a variety of reasons for determining the composition of a substance in a mixture includingcomposition of a substance in a mixture including

Determining the amount of pollutants present in Determining the amount of pollutants present in drinking waterdrinking water

Determining the amount of a metal present in an Determining the amount of a metal present in an ore sampleore sample

Quality control in the production of a variety of Quality control in the production of a variety of consumer goods (eg ensuring the correct consumer goods (eg ensuring the correct quantities of N P and K in fertilisers) quantities of N P and K in fertilisers)

Soil testing to determine suitability for plantcrop Soil testing to determine suitability for plantcrop growthgrowth

Gravimetric AnalysisGravimetric AnalysisGravimetric analysis involves the use of a variety of Gravimetric analysis involves the use of a variety of

separation techniques followed by a simple calculation to separation techniques followed by a simple calculation to determine the percentage composition of a substancedetermine the percentage composition of a substance

For exampleFor exampleA sample of ore weighing 1063g is found to contain 155g of A sample of ore weighing 1063g is found to contain 155g of

nickel (Ni) and 076g of cobalt (Co) Calculate the nickel (Ni) and 076g of cobalt (Co) Calculate the composition of Ni and Cocomposition of Ni and Co

component = component = mass of component in samplemass of component in sample x 100 x 100 total mass of sampletotal mass of sample

NiNi = 155g1063g x 100 = = 155g1063g x 100 = 14581458

CoCo = 076g1063g x 100 = = 076g1063g x 100 = 715715

Class AssignmentClass Assignment

Choose a mixture from one of the 4 spheres of the Earth and gather Choose a mixture from one of the 4 spheres of the Earth and gather information about the followinginformation about the following

Industrial separation processes to separate the mixtureIndustrial separation processes to separate the mixture The properties of the mixture that are used in these separation The properties of the mixture that are used in these separation

processesprocesses The products of separation and their usesThe products of separation and their uses The issues associated with wastes generated from these The issues associated with wastes generated from these

processesprocesses

Present your information in Report Style with supporting diagrams Present your information in Report Style with supporting diagrams and a source list and a source list

82 The Chemical Earth82 The Chemical Earth

Focus 2Focus 2Although most elements are found in Although most elements are found in

combinations on Earth some elements are combinations on Earth some elements are found uncombinedfound uncombined

Properties of the Properties of the ElementsElements

Elements are classified into three categories based on their Elements are classified into three categories based on their physical propertiesphysical properties

The 3 categories areThe 3 categories are

MetalsMetals Non-metalsNon-metals Semi-metals or metaloidsSemi-metals or metaloids

Some of the physical properties used in this classificationSome of the physical properties used in this classification

Density (massvolume)Density (massvolume) Boiling pointmelting pointBoiling pointmelting point Electrical and Thermal conductivityElectrical and Thermal conductivity State at room temperature (solid liquid or gas)State at room temperature (solid liquid or gas) AppearanceAppearance

The Periodic TableThe Periodic Table

httplibrarytedankarak12trchemistryvol1atomstrtrans50jpg

Percentage compositionPercentage composition

Quantitative Analysis of a substance involves Quantitative Analysis of a substance involves the determination of actual percentages the determination of actual percentages present in a sample present in a sample

This involves eitherThis involves either11 VolumetricVolumetric analysis-involves measuring analysis-involves measuring

percentages by volumepercentages by volume22 GravimetricGravimetric analysis-involves measuring analysis-involves measuring

percentages by massweightpercentages by massweight

In either case the calculations will be similarIn either case the calculations will be similar

Gravimetric AnalysisGravimetric Analysis

There are a variety of reasons for determining the There are a variety of reasons for determining the composition of a substance in a mixture includingcomposition of a substance in a mixture including

Determining the amount of pollutants present in Determining the amount of pollutants present in drinking waterdrinking water

Determining the amount of a metal present in an Determining the amount of a metal present in an ore sampleore sample

Quality control in the production of a variety of Quality control in the production of a variety of consumer goods (eg ensuring the correct consumer goods (eg ensuring the correct quantities of N P and K in fertilisers) quantities of N P and K in fertilisers)

Soil testing to determine suitability for plantcrop Soil testing to determine suitability for plantcrop growthgrowth

Gravimetric AnalysisGravimetric AnalysisGravimetric analysis involves the use of a variety of Gravimetric analysis involves the use of a variety of

separation techniques followed by a simple calculation to separation techniques followed by a simple calculation to determine the percentage composition of a substancedetermine the percentage composition of a substance

For exampleFor exampleA sample of ore weighing 1063g is found to contain 155g of A sample of ore weighing 1063g is found to contain 155g of

nickel (Ni) and 076g of cobalt (Co) Calculate the nickel (Ni) and 076g of cobalt (Co) Calculate the composition of Ni and Cocomposition of Ni and Co

component = component = mass of component in samplemass of component in sample x 100 x 100 total mass of sampletotal mass of sample

NiNi = 155g1063g x 100 = = 155g1063g x 100 = 14581458

CoCo = 076g1063g x 100 = = 076g1063g x 100 = 715715

Class AssignmentClass Assignment

Choose a mixture from one of the 4 spheres of the Earth and gather Choose a mixture from one of the 4 spheres of the Earth and gather information about the followinginformation about the following

Industrial separation processes to separate the mixtureIndustrial separation processes to separate the mixture The properties of the mixture that are used in these separation The properties of the mixture that are used in these separation

processesprocesses The products of separation and their usesThe products of separation and their uses The issues associated with wastes generated from these The issues associated with wastes generated from these

processesprocesses

Present your information in Report Style with supporting diagrams Present your information in Report Style with supporting diagrams and a source list and a source list

82 The Chemical Earth82 The Chemical Earth

Focus 2Focus 2Although most elements are found in Although most elements are found in

combinations on Earth some elements are combinations on Earth some elements are found uncombinedfound uncombined

Properties of the Properties of the ElementsElements

Elements are classified into three categories based on their Elements are classified into three categories based on their physical propertiesphysical properties

The 3 categories areThe 3 categories are

MetalsMetals Non-metalsNon-metals Semi-metals or metaloidsSemi-metals or metaloids

Some of the physical properties used in this classificationSome of the physical properties used in this classification

Density (massvolume)Density (massvolume) Boiling pointmelting pointBoiling pointmelting point Electrical and Thermal conductivityElectrical and Thermal conductivity State at room temperature (solid liquid or gas)State at room temperature (solid liquid or gas) AppearanceAppearance

The Periodic TableThe Periodic Table

httplibrarytedankarak12trchemistryvol1atomstrtrans50jpg

Gravimetric AnalysisGravimetric Analysis

There are a variety of reasons for determining the There are a variety of reasons for determining the composition of a substance in a mixture includingcomposition of a substance in a mixture including

Determining the amount of pollutants present in Determining the amount of pollutants present in drinking waterdrinking water

Determining the amount of a metal present in an Determining the amount of a metal present in an ore sampleore sample

Quality control in the production of a variety of Quality control in the production of a variety of consumer goods (eg ensuring the correct consumer goods (eg ensuring the correct quantities of N P and K in fertilisers) quantities of N P and K in fertilisers)

Soil testing to determine suitability for plantcrop Soil testing to determine suitability for plantcrop growthgrowth

Gravimetric AnalysisGravimetric AnalysisGravimetric analysis involves the use of a variety of Gravimetric analysis involves the use of a variety of

separation techniques followed by a simple calculation to separation techniques followed by a simple calculation to determine the percentage composition of a substancedetermine the percentage composition of a substance

For exampleFor exampleA sample of ore weighing 1063g is found to contain 155g of A sample of ore weighing 1063g is found to contain 155g of

nickel (Ni) and 076g of cobalt (Co) Calculate the nickel (Ni) and 076g of cobalt (Co) Calculate the composition of Ni and Cocomposition of Ni and Co

component = component = mass of component in samplemass of component in sample x 100 x 100 total mass of sampletotal mass of sample

NiNi = 155g1063g x 100 = = 155g1063g x 100 = 14581458

CoCo = 076g1063g x 100 = = 076g1063g x 100 = 715715

Class AssignmentClass Assignment

Choose a mixture from one of the 4 spheres of the Earth and gather Choose a mixture from one of the 4 spheres of the Earth and gather information about the followinginformation about the following

Industrial separation processes to separate the mixtureIndustrial separation processes to separate the mixture The properties of the mixture that are used in these separation The properties of the mixture that are used in these separation

processesprocesses The products of separation and their usesThe products of separation and their uses The issues associated with wastes generated from these The issues associated with wastes generated from these

processesprocesses

Present your information in Report Style with supporting diagrams Present your information in Report Style with supporting diagrams and a source list and a source list

82 The Chemical Earth82 The Chemical Earth

Focus 2Focus 2Although most elements are found in Although most elements are found in

combinations on Earth some elements are combinations on Earth some elements are found uncombinedfound uncombined

Properties of the Properties of the ElementsElements

Elements are classified into three categories based on their Elements are classified into three categories based on their physical propertiesphysical properties

The 3 categories areThe 3 categories are

MetalsMetals Non-metalsNon-metals Semi-metals or metaloidsSemi-metals or metaloids

Some of the physical properties used in this classificationSome of the physical properties used in this classification

Density (massvolume)Density (massvolume) Boiling pointmelting pointBoiling pointmelting point Electrical and Thermal conductivityElectrical and Thermal conductivity State at room temperature (solid liquid or gas)State at room temperature (solid liquid or gas) AppearanceAppearance

The Periodic TableThe Periodic Table

httplibrarytedankarak12trchemistryvol1atomstrtrans50jpg

Gravimetric AnalysisGravimetric AnalysisGravimetric analysis involves the use of a variety of Gravimetric analysis involves the use of a variety of

separation techniques followed by a simple calculation to separation techniques followed by a simple calculation to determine the percentage composition of a substancedetermine the percentage composition of a substance

For exampleFor exampleA sample of ore weighing 1063g is found to contain 155g of A sample of ore weighing 1063g is found to contain 155g of

nickel (Ni) and 076g of cobalt (Co) Calculate the nickel (Ni) and 076g of cobalt (Co) Calculate the composition of Ni and Cocomposition of Ni and Co

component = component = mass of component in samplemass of component in sample x 100 x 100 total mass of sampletotal mass of sample

NiNi = 155g1063g x 100 = = 155g1063g x 100 = 14581458

CoCo = 076g1063g x 100 = = 076g1063g x 100 = 715715

Class AssignmentClass Assignment

Choose a mixture from one of the 4 spheres of the Earth and gather Choose a mixture from one of the 4 spheres of the Earth and gather information about the followinginformation about the following

Industrial separation processes to separate the mixtureIndustrial separation processes to separate the mixture The properties of the mixture that are used in these separation The properties of the mixture that are used in these separation

processesprocesses The products of separation and their usesThe products of separation and their uses The issues associated with wastes generated from these The issues associated with wastes generated from these

processesprocesses

Present your information in Report Style with supporting diagrams Present your information in Report Style with supporting diagrams and a source list and a source list

82 The Chemical Earth82 The Chemical Earth

Focus 2Focus 2Although most elements are found in Although most elements are found in

combinations on Earth some elements are combinations on Earth some elements are found uncombinedfound uncombined

Properties of the Properties of the ElementsElements

Elements are classified into three categories based on their Elements are classified into three categories based on their physical propertiesphysical properties

The 3 categories areThe 3 categories are

MetalsMetals Non-metalsNon-metals Semi-metals or metaloidsSemi-metals or metaloids

Some of the physical properties used in this classificationSome of the physical properties used in this classification

Density (massvolume)Density (massvolume) Boiling pointmelting pointBoiling pointmelting point Electrical and Thermal conductivityElectrical and Thermal conductivity State at room temperature (solid liquid or gas)State at room temperature (solid liquid or gas) AppearanceAppearance

The Periodic TableThe Periodic Table

httplibrarytedankarak12trchemistryvol1atomstrtrans50jpg

Class AssignmentClass Assignment

Choose a mixture from one of the 4 spheres of the Earth and gather Choose a mixture from one of the 4 spheres of the Earth and gather information about the followinginformation about the following

Industrial separation processes to separate the mixtureIndustrial separation processes to separate the mixture The properties of the mixture that are used in these separation The properties of the mixture that are used in these separation

processesprocesses The products of separation and their usesThe products of separation and their uses The issues associated with wastes generated from these The issues associated with wastes generated from these

processesprocesses

Present your information in Report Style with supporting diagrams Present your information in Report Style with supporting diagrams and a source list and a source list

82 The Chemical Earth82 The Chemical Earth

Focus 2Focus 2Although most elements are found in Although most elements are found in

combinations on Earth some elements are combinations on Earth some elements are found uncombinedfound uncombined

Properties of the Properties of the ElementsElements

Elements are classified into three categories based on their Elements are classified into three categories based on their physical propertiesphysical properties

The 3 categories areThe 3 categories are

MetalsMetals Non-metalsNon-metals Semi-metals or metaloidsSemi-metals or metaloids

Some of the physical properties used in this classificationSome of the physical properties used in this classification

Density (massvolume)Density (massvolume) Boiling pointmelting pointBoiling pointmelting point Electrical and Thermal conductivityElectrical and Thermal conductivity State at room temperature (solid liquid or gas)State at room temperature (solid liquid or gas) AppearanceAppearance

The Periodic TableThe Periodic Table

httplibrarytedankarak12trchemistryvol1atomstrtrans50jpg

82 The Chemical Earth82 The Chemical Earth

Focus 2Focus 2Although most elements are found in Although most elements are found in

combinations on Earth some elements are combinations on Earth some elements are found uncombinedfound uncombined

Properties of the Properties of the ElementsElements

Elements are classified into three categories based on their Elements are classified into three categories based on their physical propertiesphysical properties

The 3 categories areThe 3 categories are

MetalsMetals Non-metalsNon-metals Semi-metals or metaloidsSemi-metals or metaloids

Some of the physical properties used in this classificationSome of the physical properties used in this classification

Density (massvolume)Density (massvolume) Boiling pointmelting pointBoiling pointmelting point Electrical and Thermal conductivityElectrical and Thermal conductivity State at room temperature (solid liquid or gas)State at room temperature (solid liquid or gas) AppearanceAppearance

The Periodic TableThe Periodic Table

httplibrarytedankarak12trchemistryvol1atomstrtrans50jpg

Properties of the Properties of the ElementsElements

Elements are classified into three categories based on their Elements are classified into three categories based on their physical propertiesphysical properties

The 3 categories areThe 3 categories are

MetalsMetals Non-metalsNon-metals Semi-metals or metaloidsSemi-metals or metaloids

Some of the physical properties used in this classificationSome of the physical properties used in this classification

Density (massvolume)Density (massvolume) Boiling pointmelting pointBoiling pointmelting point Electrical and Thermal conductivityElectrical and Thermal conductivity State at room temperature (solid liquid or gas)State at room temperature (solid liquid or gas) AppearanceAppearance

The Periodic TableThe Periodic Table

httplibrarytedankarak12trchemistryvol1atomstrtrans50jpg

The Periodic TableThe Periodic Table

httplibrarytedankarak12trchemistryvol1atomstrtrans50jpg

httpwwwdayahcomperiodicImagesperiodic20tablepng

Properties of the Properties of the ElementsElements

Metals Metals (eg Fe Cu Mg Al Au)(eg Fe Cu Mg Al Au) solid at room temperature (except Hg) and solid at room temperature (except Hg) and

usually densehardusually densehard usually high meltingboiling pointsusually high meltingboiling points have a shiny (lustrous) appearancehave a shiny (lustrous) appearance are malleable (able to be hammered into sheets)are malleable (able to be hammered into sheets) are ductile (able to be drawn into wires)are ductile (able to be drawn into wires) are good conductors of heat and electricityare good conductors of heat and electricity

Uses construction materials utensils electrical Uses construction materials utensils electrical wiring household appliances drink cans etcwiring household appliances drink cans etc

Properties of the Properties of the ElementsElements

Non-metalsNon-metals (eg C S He Cl) (eg C S He Cl) can be solid liquid or gas at room temperaturecan be solid liquid or gas at room temperature usually have relatively low meltingboiling pointsusually have relatively low meltingboiling points are usually not lustrousare usually not lustrous are usually brittle not malleable or ductileare usually brittle not malleable or ductile Are poor conductors of heat and electricity (except Are poor conductors of heat and electricity (except

for C in the form of graphite)for C in the form of graphite)

Uses Uses carboncarbon used as an electrode in dry cells and is used as an electrode in dry cells and is the ldquoleadrdquo in pencils the ldquoleadrdquo in pencils sulfursulfur used in vulcanising used in vulcanising rubber rubber neonneon is used in ldquoneonrdquo signs and is used in ldquoneonrdquo signs and chlorinechlorine is used in bleach and swimming pools as well as in is used in bleach and swimming pools as well as in the production of plastics such as PVCthe production of plastics such as PVC

Properties of the Properties of the ElementsElements

Semi-metalsSemi-metals (B Si Ge As Sb) (B Si Ge As Sb) have properties that are a combination of metal have properties that are a combination of metal

and non-metal propertiesand non-metal properties usually have high meltingboiling pointsusually have high meltingboiling points have variable conductivities depending upon have variable conductivities depending upon

temperature but are usually lowtemperature but are usually low have variable appearancehave variable appearance

Uses mixtures of silicon and germanium are used Uses mixtures of silicon and germanium are used as semi-conductors in transistors and computer as semi-conductors in transistors and computer chips They can be mixed with other elements chips They can be mixed with other elements (eg As and B) to increase their conductivities(eg As and B) to increase their conductivities

Reactivity of the Reactivity of the ElementsElements

The elements vary greatly in their reactivity How reactive an The elements vary greatly in their reactivity How reactive an element is directly related to how the electrons are arranged in element is directly related to how the electrons are arranged in the atom influencing what form it will take in naturethe atom influencing what form it will take in nature

Some elements are not very reactive and are therefore found Some elements are not very reactive and are therefore found uncombined in nature These include uncombined in nature These include the noble gases (He Ne the noble gases (He Ne Ar Kr Xe Rn) and the metals Au Ag Pt and Cu (sometimes) Ar Kr Xe Rn) and the metals Au Ag Pt and Cu (sometimes)

Some elements occur as molecules that contain only one type of Some elements occur as molecules that contain only one type of atom These are referred to as molecular elements These are atom These are referred to as molecular elements These are also found combined with other elements in compounds These also found combined with other elements in compounds These include include OO22 N N22 H H22 Cl Cl22 I I22 P P4 4

Most of the elements are reactive and therefore occur as Most of the elements are reactive and therefore occur as compounds in nature These include compounds in nature These include NaCl HNaCl H22SOSO44 SiO SiO22

General rule The more reactive an element is the less of a chance it will be found uncombined in nature

82 The Chemical Earth82 The Chemical Earth

Focus 3Focus 3

Elements in Earth materials are present Elements in Earth materials are present mostly as compounds because of mostly as compounds because of

interactions at the atomic levelinteractions at the atomic level

The particle nature of The particle nature of mattermatter

Matter is often described as being made up of small particles that Matter is often described as being made up of small particles that are continuously moving and interacting In each of the three states are continuously moving and interacting In each of the three states of matter (solid liquid gas) the particles experience vibrational of matter (solid liquid gas) the particles experience vibrational motion Liquids and gases experience translational (movement) motion Liquids and gases experience translational (movement) motion as well Gases experience more translational motion than motion as well Gases experience more translational motion than liquids as they have more energyliquids as they have more energy

liquid gassolid

The particle nature of The particle nature of mattermatter

The primary particle in chemistry is the atom The primary particle in chemistry is the atom Atoms Atoms are defined as the smallest particle of an elementare defined as the smallest particle of an element However you probably know that there is a However you probably know that there is a substructure to an atom that it is made of substructure to an atom that it is made of protons protons neutrons and electronsneutrons and electrons You may also know that You may also know that protons and neutrons are each made of three protons and neutrons are each made of three quarksquarks

The particle nature of The particle nature of mattermatter

Each element has a Each element has a distinctive atomic distinctive atomic number and mass number and mass numbernumber

The The atomic numberatomic number (Z) (Z) corresponds to the corresponds to the number of protons in number of protons in the nucleusthe nucleus

The The mass numbermass number (A) (A) corresponds to the total corresponds to the total number of neutrons and number of neutrons and protons in the nucleusprotons in the nucleus

Mathematically

A = Z + number of neutrons

Structure of the AtomStructure of the Atom

The particles that make up the elements are The particles that make up the elements are called atoms All atoms of one element are the called atoms All atoms of one element are the same but they are different from the atoms of same but they are different from the atoms of all other elements In other words each all other elements In other words each element has a distinct type of atom with a element has a distinct type of atom with a specific number of protons neutrons and specific number of protons neutrons and electronselectrons

Protons have a +ve chargeProtons have a +ve charge Electrons have a ndashve charge Electrons have a ndashve charge Neutrons have no chargeNeutrons have no charge

Structure of the AtomStructure of the Atom

Protons (p) and Protons (p) and neutrons (n)neutrons (n) are are found in the centre of found in the centre of the atom in the the atom in the nucleus nucleus

Electrons (e)Electrons (e) are are found in the found in the surrounding space surrounding space around the nucleus around the nucleus moving randomly in moving randomly in what is known as an what is known as an lsquolsquoelectron cloudelectron cloudrsquorsquo

RelatiRelative ve massmass

RelatiRelative ve chargchargee

electrelectronon

(e)(e)

1200120000

-1-1

protonproton

(p)(p)11 +1+1

neutroneutronn

(n)(n)11 00

Structure of the AtomStructure of the Atom

IsotopesIsotopesAll atoms of the same All atoms of the same

element have the same element have the same number of protons in number of protons in the nucleus however the nucleus however they do not necessarily they do not necessarily have the same mass have the same mass These atoms differ in These atoms differ in the number of neutrons the number of neutrons and therefore the mass and therefore the mass number and are known number and are known as isotopes Some well-as isotopes Some well-known isotopes are in known isotopes are in the table to the rightthe table to the right

NameName pp

nn

ee

Hydrogen Hydrogen 11 00 11

DeuteriuDeuteriumm

11 11 11

TritiumTritium 11 22 11

Carbon Carbon 1212

66 66 66

Carbon Carbon 1313

66 77 66

Carbon Carbon 1414

66 88 66

Uranium Uranium 235235

9292 141433

9292

Uranium Uranium 238238

9292 141466

9292

Structure of the AtomStructure of the AtomThe Bohr ModelThe Bohr ModelBohrrsquos model of the atom Bohrrsquos model of the atom

consists of electrons in consists of electrons in distinct energy levels or distinct energy levels or lsquoshellsrsquo The shells closest to lsquoshellsrsquo The shells closest to the nucleus are the lowest the nucleus are the lowest energy (n=1) and lsquofillrsquo firstenergy (n=1) and lsquofillrsquo first

The maximum number of The maximum number of electrons in each shell can be electrons in each shell can be calculated by calculated by 2n2n22

ThereforeThereforen=1 maximum of 2 en=1 maximum of 2 en=2 maximum of 8 en=2 maximum of 8 en=3 maximum of 18 en=3 maximum of 18 eand so onhellipand so onhellip

The valence shell or outer shell The valence shell or outer shell can hold a maximum of 8can hold a maximum of 8

Structure of the AtomStructure of the AtomOrbitalsOrbitalsSchroumldinger used quantum mechanics to describe the shape Schroumldinger used quantum mechanics to describe the shape

of the lsquocloudsrsquo within each energy level These are called of the lsquocloudsrsquo within each energy level These are called orbitals and each energy level contains an increasing orbitals and each energy level contains an increasing number of orbitals to accommodate more electrons All number of orbitals to accommodate more electrons All energy levels contain lsquosrsquo orbitals which are spherical (one energy levels contain lsquosrsquo orbitals which are spherical (one lobe) All but the first energy level contain 3 lsquoprsquo orbitals lobe) All but the first energy level contain 3 lsquoprsquo orbitals which are dumbbell shaped (two lobes) After the first two which are dumbbell shaped (two lobes) After the first two each energy level contains 5 lsquodrsquo orbitals most of which each energy level contains 5 lsquodrsquo orbitals most of which have 4 lobes Higher energy levels contain 7 lsquofrsquo orbitals have 4 lobes Higher energy levels contain 7 lsquofrsquo orbitals Each orbital can accommodate 2 electrons ThereforeEach orbital can accommodate 2 electrons Therefore

lsquolsquosrsquo orbitals hold 2 electronssrsquo orbitals hold 2 electrons lsquolsquoprsquo orbitals hold 6 electronsprsquo orbitals hold 6 electrons lsquolsquodrsquo orbitals hold 10 electronsdrsquo orbitals hold 10 electrons lsquolsquofrsquo orbitals hold 14 electronsfrsquo orbitals hold 14 electrons

httpwebfac1enmuedulongrowwworbitalsatorbhtmNote For Interest Only You are not required to learn this information for the HSC

Properties of the Properties of the ElementsElements

Non-metalsNon-metals (eg C S He Cl) (eg C S He Cl) can be solid liquid or gas at room temperaturecan be solid liquid or gas at room temperature usually have relatively low meltingboiling pointsusually have relatively low meltingboiling points are usually not lustrousare usually not lustrous are usually brittle not malleable or ductileare usually brittle not malleable or ductile Are poor conductors of heat and electricity (except Are poor conductors of heat and electricity (except

for C in the form of graphite)for C in the form of graphite)

Uses Uses carboncarbon used as an electrode in dry cells and is used as an electrode in dry cells and is the ldquoleadrdquo in pencils the ldquoleadrdquo in pencils sulfursulfur used in vulcanising used in vulcanising rubber rubber neonneon is used in ldquoneonrdquo signs and is used in ldquoneonrdquo signs and chlorinechlorine is used in bleach and swimming pools as well as in is used in bleach and swimming pools as well as in the production of plastics such as PVCthe production of plastics such as PVC

Properties of the Properties of the ElementsElements

Semi-metalsSemi-metals (B Si Ge As Sb) (B Si Ge As Sb) have properties that are a combination of metal have properties that are a combination of metal

and non-metal propertiesand non-metal properties usually have high meltingboiling pointsusually have high meltingboiling points have variable conductivities depending upon have variable conductivities depending upon

temperature but are usually lowtemperature but are usually low have variable appearancehave variable appearance

Uses mixtures of silicon and germanium are used Uses mixtures of silicon and germanium are used as semi-conductors in transistors and computer as semi-conductors in transistors and computer chips They can be mixed with other elements chips They can be mixed with other elements (eg As and B) to increase their conductivities(eg As and B) to increase their conductivities

Reactivity of the Reactivity of the ElementsElements

The elements vary greatly in their reactivity How reactive an The elements vary greatly in their reactivity How reactive an element is directly related to how the electrons are arranged in element is directly related to how the electrons are arranged in the atom influencing what form it will take in naturethe atom influencing what form it will take in nature

Some elements are not very reactive and are therefore found Some elements are not very reactive and are therefore found uncombined in nature These include uncombined in nature These include the noble gases (He Ne the noble gases (He Ne Ar Kr Xe Rn) and the metals Au Ag Pt and Cu (sometimes) Ar Kr Xe Rn) and the metals Au Ag Pt and Cu (sometimes)

Some elements occur as molecules that contain only one type of Some elements occur as molecules that contain only one type of atom These are referred to as molecular elements These are atom These are referred to as molecular elements These are also found combined with other elements in compounds These also found combined with other elements in compounds These include include OO22 N N22 H H22 Cl Cl22 I I22 P P4 4

Most of the elements are reactive and therefore occur as Most of the elements are reactive and therefore occur as compounds in nature These include compounds in nature These include NaCl HNaCl H22SOSO44 SiO SiO22

General rule The more reactive an element is the less of a chance it will be found uncombined in nature

82 The Chemical Earth82 The Chemical Earth

Focus 3Focus 3

Elements in Earth materials are present Elements in Earth materials are present mostly as compounds because of mostly as compounds because of

interactions at the atomic levelinteractions at the atomic level

The particle nature of The particle nature of mattermatter

Matter is often described as being made up of small particles that Matter is often described as being made up of small particles that are continuously moving and interacting In each of the three states are continuously moving and interacting In each of the three states of matter (solid liquid gas) the particles experience vibrational of matter (solid liquid gas) the particles experience vibrational motion Liquids and gases experience translational (movement) motion Liquids and gases experience translational (movement) motion as well Gases experience more translational motion than motion as well Gases experience more translational motion than liquids as they have more energyliquids as they have more energy

liquid gassolid

The particle nature of The particle nature of mattermatter

The primary particle in chemistry is the atom The primary particle in chemistry is the atom Atoms Atoms are defined as the smallest particle of an elementare defined as the smallest particle of an element However you probably know that there is a However you probably know that there is a substructure to an atom that it is made of substructure to an atom that it is made of protons protons neutrons and electronsneutrons and electrons You may also know that You may also know that protons and neutrons are each made of three protons and neutrons are each made of three quarksquarks

The particle nature of The particle nature of mattermatter

Each element has a Each element has a distinctive atomic distinctive atomic number and mass number and mass numbernumber

The The atomic numberatomic number (Z) (Z) corresponds to the corresponds to the number of protons in number of protons in the nucleusthe nucleus

The The mass numbermass number (A) (A) corresponds to the total corresponds to the total number of neutrons and number of neutrons and protons in the nucleusprotons in the nucleus

Mathematically

A = Z + number of neutrons

Structure of the AtomStructure of the Atom

The particles that make up the elements are The particles that make up the elements are called atoms All atoms of one element are the called atoms All atoms of one element are the same but they are different from the atoms of same but they are different from the atoms of all other elements In other words each all other elements In other words each element has a distinct type of atom with a element has a distinct type of atom with a specific number of protons neutrons and specific number of protons neutrons and electronselectrons

Protons have a +ve chargeProtons have a +ve charge Electrons have a ndashve charge Electrons have a ndashve charge Neutrons have no chargeNeutrons have no charge

Structure of the AtomStructure of the Atom

Protons (p) and Protons (p) and neutrons (n)neutrons (n) are are found in the centre of found in the centre of the atom in the the atom in the nucleus nucleus

Electrons (e)Electrons (e) are are found in the found in the surrounding space surrounding space around the nucleus around the nucleus moving randomly in moving randomly in what is known as an what is known as an lsquolsquoelectron cloudelectron cloudrsquorsquo

RelatiRelative ve massmass

RelatiRelative ve chargchargee

electrelectronon

(e)(e)

1200120000

-1-1

protonproton

(p)(p)11 +1+1

neutroneutronn

(n)(n)11 00

Structure of the AtomStructure of the Atom

IsotopesIsotopesAll atoms of the same All atoms of the same

element have the same element have the same number of protons in number of protons in the nucleus however the nucleus however they do not necessarily they do not necessarily have the same mass have the same mass These atoms differ in These atoms differ in the number of neutrons the number of neutrons and therefore the mass and therefore the mass number and are known number and are known as isotopes Some well-as isotopes Some well-known isotopes are in known isotopes are in the table to the rightthe table to the right

NameName pp

nn

ee

Hydrogen Hydrogen 11 00 11

DeuteriuDeuteriumm

11 11 11

TritiumTritium 11 22 11

Carbon Carbon 1212

66 66 66

Carbon Carbon 1313

66 77 66

Carbon Carbon 1414

66 88 66

Uranium Uranium 235235

9292 141433

9292

Uranium Uranium 238238

9292 141466

9292

Structure of the AtomStructure of the AtomThe Bohr ModelThe Bohr ModelBohrrsquos model of the atom Bohrrsquos model of the atom

consists of electrons in consists of electrons in distinct energy levels or distinct energy levels or lsquoshellsrsquo The shells closest to lsquoshellsrsquo The shells closest to the nucleus are the lowest the nucleus are the lowest energy (n=1) and lsquofillrsquo firstenergy (n=1) and lsquofillrsquo first

The maximum number of The maximum number of electrons in each shell can be electrons in each shell can be calculated by calculated by 2n2n22

ThereforeThereforen=1 maximum of 2 en=1 maximum of 2 en=2 maximum of 8 en=2 maximum of 8 en=3 maximum of 18 en=3 maximum of 18 eand so onhellipand so onhellip

The valence shell or outer shell The valence shell or outer shell can hold a maximum of 8can hold a maximum of 8

Structure of the AtomStructure of the AtomOrbitalsOrbitalsSchroumldinger used quantum mechanics to describe the shape Schroumldinger used quantum mechanics to describe the shape

of the lsquocloudsrsquo within each energy level These are called of the lsquocloudsrsquo within each energy level These are called orbitals and each energy level contains an increasing orbitals and each energy level contains an increasing number of orbitals to accommodate more electrons All number of orbitals to accommodate more electrons All energy levels contain lsquosrsquo orbitals which are spherical (one energy levels contain lsquosrsquo orbitals which are spherical (one lobe) All but the first energy level contain 3 lsquoprsquo orbitals lobe) All but the first energy level contain 3 lsquoprsquo orbitals which are dumbbell shaped (two lobes) After the first two which are dumbbell shaped (two lobes) After the first two each energy level contains 5 lsquodrsquo orbitals most of which each energy level contains 5 lsquodrsquo orbitals most of which have 4 lobes Higher energy levels contain 7 lsquofrsquo orbitals have 4 lobes Higher energy levels contain 7 lsquofrsquo orbitals Each orbital can accommodate 2 electrons ThereforeEach orbital can accommodate 2 electrons Therefore

lsquolsquosrsquo orbitals hold 2 electronssrsquo orbitals hold 2 electrons lsquolsquoprsquo orbitals hold 6 electronsprsquo orbitals hold 6 electrons lsquolsquodrsquo orbitals hold 10 electronsdrsquo orbitals hold 10 electrons lsquolsquofrsquo orbitals hold 14 electronsfrsquo orbitals hold 14 electrons

httpwebfac1enmuedulongrowwworbitalsatorbhtmNote For Interest Only You are not required to learn this information for the HSC

Properties of the Properties of the ElementsElements

Semi-metalsSemi-metals (B Si Ge As Sb) (B Si Ge As Sb) have properties that are a combination of metal have properties that are a combination of metal

and non-metal propertiesand non-metal properties usually have high meltingboiling pointsusually have high meltingboiling points have variable conductivities depending upon have variable conductivities depending upon

temperature but are usually lowtemperature but are usually low have variable appearancehave variable appearance

Uses mixtures of silicon and germanium are used Uses mixtures of silicon and germanium are used as semi-conductors in transistors and computer as semi-conductors in transistors and computer chips They can be mixed with other elements chips They can be mixed with other elements (eg As and B) to increase their conductivities(eg As and B) to increase their conductivities

Reactivity of the Reactivity of the ElementsElements

The elements vary greatly in their reactivity How reactive an The elements vary greatly in their reactivity How reactive an element is directly related to how the electrons are arranged in element is directly related to how the electrons are arranged in the atom influencing what form it will take in naturethe atom influencing what form it will take in nature

Some elements are not very reactive and are therefore found Some elements are not very reactive and are therefore found uncombined in nature These include uncombined in nature These include the noble gases (He Ne the noble gases (He Ne Ar Kr Xe Rn) and the metals Au Ag Pt and Cu (sometimes) Ar Kr Xe Rn) and the metals Au Ag Pt and Cu (sometimes)

Some elements occur as molecules that contain only one type of Some elements occur as molecules that contain only one type of atom These are referred to as molecular elements These are atom These are referred to as molecular elements These are also found combined with other elements in compounds These also found combined with other elements in compounds These include include OO22 N N22 H H22 Cl Cl22 I I22 P P4 4

Most of the elements are reactive and therefore occur as Most of the elements are reactive and therefore occur as compounds in nature These include compounds in nature These include NaCl HNaCl H22SOSO44 SiO SiO22

General rule The more reactive an element is the less of a chance it will be found uncombined in nature

82 The Chemical Earth82 The Chemical Earth

Focus 3Focus 3

Elements in Earth materials are present Elements in Earth materials are present mostly as compounds because of mostly as compounds because of

interactions at the atomic levelinteractions at the atomic level

The particle nature of The particle nature of mattermatter

Matter is often described as being made up of small particles that Matter is often described as being made up of small particles that are continuously moving and interacting In each of the three states are continuously moving and interacting In each of the three states of matter (solid liquid gas) the particles experience vibrational of matter (solid liquid gas) the particles experience vibrational motion Liquids and gases experience translational (movement) motion Liquids and gases experience translational (movement) motion as well Gases experience more translational motion than motion as well Gases experience more translational motion than liquids as they have more energyliquids as they have more energy

liquid gassolid

The particle nature of The particle nature of mattermatter

The primary particle in chemistry is the atom The primary particle in chemistry is the atom Atoms Atoms are defined as the smallest particle of an elementare defined as the smallest particle of an element However you probably know that there is a However you probably know that there is a substructure to an atom that it is made of substructure to an atom that it is made of protons protons neutrons and electronsneutrons and electrons You may also know that You may also know that protons and neutrons are each made of three protons and neutrons are each made of three quarksquarks

The particle nature of The particle nature of mattermatter

Each element has a Each element has a distinctive atomic distinctive atomic number and mass number and mass numbernumber

The The atomic numberatomic number (Z) (Z) corresponds to the corresponds to the number of protons in number of protons in the nucleusthe nucleus

The The mass numbermass number (A) (A) corresponds to the total corresponds to the total number of neutrons and number of neutrons and protons in the nucleusprotons in the nucleus

Mathematically

A = Z + number of neutrons

Structure of the AtomStructure of the Atom

The particles that make up the elements are The particles that make up the elements are called atoms All atoms of one element are the called atoms All atoms of one element are the same but they are different from the atoms of same but they are different from the atoms of all other elements In other words each all other elements In other words each element has a distinct type of atom with a element has a distinct type of atom with a specific number of protons neutrons and specific number of protons neutrons and electronselectrons

Protons have a +ve chargeProtons have a +ve charge Electrons have a ndashve charge Electrons have a ndashve charge Neutrons have no chargeNeutrons have no charge

Structure of the AtomStructure of the Atom

Protons (p) and Protons (p) and neutrons (n)neutrons (n) are are found in the centre of found in the centre of the atom in the the atom in the nucleus nucleus

Electrons (e)Electrons (e) are are found in the found in the surrounding space surrounding space around the nucleus around the nucleus moving randomly in moving randomly in what is known as an what is known as an lsquolsquoelectron cloudelectron cloudrsquorsquo

RelatiRelative ve massmass

RelatiRelative ve chargchargee

electrelectronon

(e)(e)

1200120000

-1-1

protonproton

(p)(p)11 +1+1

neutroneutronn

(n)(n)11 00

Structure of the AtomStructure of the Atom

IsotopesIsotopesAll atoms of the same All atoms of the same

element have the same element have the same number of protons in number of protons in the nucleus however the nucleus however they do not necessarily they do not necessarily have the same mass have the same mass These atoms differ in These atoms differ in the number of neutrons the number of neutrons and therefore the mass and therefore the mass number and are known number and are known as isotopes Some well-as isotopes Some well-known isotopes are in known isotopes are in the table to the rightthe table to the right

NameName pp

nn

ee

Hydrogen Hydrogen 11 00 11

DeuteriuDeuteriumm

11 11 11

TritiumTritium 11 22 11

Carbon Carbon 1212

66 66 66

Carbon Carbon 1313

66 77 66

Carbon Carbon 1414

66 88 66

Uranium Uranium 235235

9292 141433

9292

Uranium Uranium 238238

9292 141466

9292

Structure of the AtomStructure of the AtomThe Bohr ModelThe Bohr ModelBohrrsquos model of the atom Bohrrsquos model of the atom

consists of electrons in consists of electrons in distinct energy levels or distinct energy levels or lsquoshellsrsquo The shells closest to lsquoshellsrsquo The shells closest to the nucleus are the lowest the nucleus are the lowest energy (n=1) and lsquofillrsquo firstenergy (n=1) and lsquofillrsquo first

The maximum number of The maximum number of electrons in each shell can be electrons in each shell can be calculated by calculated by 2n2n22

ThereforeThereforen=1 maximum of 2 en=1 maximum of 2 en=2 maximum of 8 en=2 maximum of 8 en=3 maximum of 18 en=3 maximum of 18 eand so onhellipand so onhellip

The valence shell or outer shell The valence shell or outer shell can hold a maximum of 8can hold a maximum of 8

Structure of the AtomStructure of the AtomOrbitalsOrbitalsSchroumldinger used quantum mechanics to describe the shape Schroumldinger used quantum mechanics to describe the shape

of the lsquocloudsrsquo within each energy level These are called of the lsquocloudsrsquo within each energy level These are called orbitals and each energy level contains an increasing orbitals and each energy level contains an increasing number of orbitals to accommodate more electrons All number of orbitals to accommodate more electrons All energy levels contain lsquosrsquo orbitals which are spherical (one energy levels contain lsquosrsquo orbitals which are spherical (one lobe) All but the first energy level contain 3 lsquoprsquo orbitals lobe) All but the first energy level contain 3 lsquoprsquo orbitals which are dumbbell shaped (two lobes) After the first two which are dumbbell shaped (two lobes) After the first two each energy level contains 5 lsquodrsquo orbitals most of which each energy level contains 5 lsquodrsquo orbitals most of which have 4 lobes Higher energy levels contain 7 lsquofrsquo orbitals have 4 lobes Higher energy levels contain 7 lsquofrsquo orbitals Each orbital can accommodate 2 electrons ThereforeEach orbital can accommodate 2 electrons Therefore

lsquolsquosrsquo orbitals hold 2 electronssrsquo orbitals hold 2 electrons lsquolsquoprsquo orbitals hold 6 electronsprsquo orbitals hold 6 electrons lsquolsquodrsquo orbitals hold 10 electronsdrsquo orbitals hold 10 electrons lsquolsquofrsquo orbitals hold 14 electronsfrsquo orbitals hold 14 electrons

httpwebfac1enmuedulongrowwworbitalsatorbhtmNote For Interest Only You are not required to learn this information for the HSC

Reactivity of the Reactivity of the ElementsElements

The elements vary greatly in their reactivity How reactive an The elements vary greatly in their reactivity How reactive an element is directly related to how the electrons are arranged in element is directly related to how the electrons are arranged in the atom influencing what form it will take in naturethe atom influencing what form it will take in nature

Some elements are not very reactive and are therefore found Some elements are not very reactive and are therefore found uncombined in nature These include uncombined in nature These include the noble gases (He Ne the noble gases (He Ne Ar Kr Xe Rn) and the metals Au Ag Pt and Cu (sometimes) Ar Kr Xe Rn) and the metals Au Ag Pt and Cu (sometimes)

Some elements occur as molecules that contain only one type of Some elements occur as molecules that contain only one type of atom These are referred to as molecular elements These are atom These are referred to as molecular elements These are also found combined with other elements in compounds These also found combined with other elements in compounds These include include OO22 N N22 H H22 Cl Cl22 I I22 P P4 4

Most of the elements are reactive and therefore occur as Most of the elements are reactive and therefore occur as compounds in nature These include compounds in nature These include NaCl HNaCl H22SOSO44 SiO SiO22

General rule The more reactive an element is the less of a chance it will be found uncombined in nature

82 The Chemical Earth82 The Chemical Earth

Focus 3Focus 3

Elements in Earth materials are present Elements in Earth materials are present mostly as compounds because of mostly as compounds because of

interactions at the atomic levelinteractions at the atomic level

The particle nature of The particle nature of mattermatter

Matter is often described as being made up of small particles that Matter is often described as being made up of small particles that are continuously moving and interacting In each of the three states are continuously moving and interacting In each of the three states of matter (solid liquid gas) the particles experience vibrational of matter (solid liquid gas) the particles experience vibrational motion Liquids and gases experience translational (movement) motion Liquids and gases experience translational (movement) motion as well Gases experience more translational motion than motion as well Gases experience more translational motion than liquids as they have more energyliquids as they have more energy

liquid gassolid

The particle nature of The particle nature of mattermatter

The primary particle in chemistry is the atom The primary particle in chemistry is the atom Atoms Atoms are defined as the smallest particle of an elementare defined as the smallest particle of an element However you probably know that there is a However you probably know that there is a substructure to an atom that it is made of substructure to an atom that it is made of protons protons neutrons and electronsneutrons and electrons You may also know that You may also know that protons and neutrons are each made of three protons and neutrons are each made of three quarksquarks

The particle nature of The particle nature of mattermatter

Each element has a Each element has a distinctive atomic distinctive atomic number and mass number and mass numbernumber

The The atomic numberatomic number (Z) (Z) corresponds to the corresponds to the number of protons in number of protons in the nucleusthe nucleus

The The mass numbermass number (A) (A) corresponds to the total corresponds to the total number of neutrons and number of neutrons and protons in the nucleusprotons in the nucleus

Mathematically

A = Z + number of neutrons

Structure of the AtomStructure of the Atom

The particles that make up the elements are The particles that make up the elements are called atoms All atoms of one element are the called atoms All atoms of one element are the same but they are different from the atoms of same but they are different from the atoms of all other elements In other words each all other elements In other words each element has a distinct type of atom with a element has a distinct type of atom with a specific number of protons neutrons and specific number of protons neutrons and electronselectrons

Protons have a +ve chargeProtons have a +ve charge Electrons have a ndashve charge Electrons have a ndashve charge Neutrons have no chargeNeutrons have no charge

Structure of the AtomStructure of the Atom

Protons (p) and Protons (p) and neutrons (n)neutrons (n) are are found in the centre of found in the centre of the atom in the the atom in the nucleus nucleus

Electrons (e)Electrons (e) are are found in the found in the surrounding space surrounding space around the nucleus around the nucleus moving randomly in moving randomly in what is known as an what is known as an lsquolsquoelectron cloudelectron cloudrsquorsquo

RelatiRelative ve massmass

RelatiRelative ve chargchargee

electrelectronon

(e)(e)

1200120000

-1-1

protonproton

(p)(p)11 +1+1

neutroneutronn

(n)(n)11 00

Structure of the AtomStructure of the Atom

IsotopesIsotopesAll atoms of the same All atoms of the same

element have the same element have the same number of protons in number of protons in the nucleus however the nucleus however they do not necessarily they do not necessarily have the same mass have the same mass These atoms differ in These atoms differ in the number of neutrons the number of neutrons and therefore the mass and therefore the mass number and are known number and are known as isotopes Some well-as isotopes Some well-known isotopes are in known isotopes are in the table to the rightthe table to the right

NameName pp

nn

ee

Hydrogen Hydrogen 11 00 11

DeuteriuDeuteriumm

11 11 11

TritiumTritium 11 22 11

Carbon Carbon 1212

66 66 66

Carbon Carbon 1313

66 77 66

Carbon Carbon 1414

66 88 66

Uranium Uranium 235235

9292 141433

9292

Uranium Uranium 238238

9292 141466

9292

Structure of the AtomStructure of the AtomThe Bohr ModelThe Bohr ModelBohrrsquos model of the atom Bohrrsquos model of the atom

consists of electrons in consists of electrons in distinct energy levels or distinct energy levels or lsquoshellsrsquo The shells closest to lsquoshellsrsquo The shells closest to the nucleus are the lowest the nucleus are the lowest energy (n=1) and lsquofillrsquo firstenergy (n=1) and lsquofillrsquo first

The maximum number of The maximum number of electrons in each shell can be electrons in each shell can be calculated by calculated by 2n2n22

ThereforeThereforen=1 maximum of 2 en=1 maximum of 2 en=2 maximum of 8 en=2 maximum of 8 en=3 maximum of 18 en=3 maximum of 18 eand so onhellipand so onhellip

The valence shell or outer shell The valence shell or outer shell can hold a maximum of 8can hold a maximum of 8

Structure of the AtomStructure of the AtomOrbitalsOrbitalsSchroumldinger used quantum mechanics to describe the shape Schroumldinger used quantum mechanics to describe the shape

of the lsquocloudsrsquo within each energy level These are called of the lsquocloudsrsquo within each energy level These are called orbitals and each energy level contains an increasing orbitals and each energy level contains an increasing number of orbitals to accommodate more electrons All number of orbitals to accommodate more electrons All energy levels contain lsquosrsquo orbitals which are spherical (one energy levels contain lsquosrsquo orbitals which are spherical (one lobe) All but the first energy level contain 3 lsquoprsquo orbitals lobe) All but the first energy level contain 3 lsquoprsquo orbitals which are dumbbell shaped (two lobes) After the first two which are dumbbell shaped (two lobes) After the first two each energy level contains 5 lsquodrsquo orbitals most of which each energy level contains 5 lsquodrsquo orbitals most of which have 4 lobes Higher energy levels contain 7 lsquofrsquo orbitals have 4 lobes Higher energy levels contain 7 lsquofrsquo orbitals Each orbital can accommodate 2 electrons ThereforeEach orbital can accommodate 2 electrons Therefore

lsquolsquosrsquo orbitals hold 2 electronssrsquo orbitals hold 2 electrons lsquolsquoprsquo orbitals hold 6 electronsprsquo orbitals hold 6 electrons lsquolsquodrsquo orbitals hold 10 electronsdrsquo orbitals hold 10 electrons lsquolsquofrsquo orbitals hold 14 electronsfrsquo orbitals hold 14 electrons

httpwebfac1enmuedulongrowwworbitalsatorbhtmNote For Interest Only You are not required to learn this information for the HSC

82 The Chemical Earth82 The Chemical Earth

Focus 3Focus 3

Elements in Earth materials are present Elements in Earth materials are present mostly as compounds because of mostly as compounds because of

interactions at the atomic levelinteractions at the atomic level

The particle nature of The particle nature of mattermatter

Matter is often described as being made up of small particles that Matter is often described as being made up of small particles that are continuously moving and interacting In each of the three states are continuously moving and interacting In each of the three states of matter (solid liquid gas) the particles experience vibrational of matter (solid liquid gas) the particles experience vibrational motion Liquids and gases experience translational (movement) motion Liquids and gases experience translational (movement) motion as well Gases experience more translational motion than motion as well Gases experience more translational motion than liquids as they have more energyliquids as they have more energy

liquid gassolid

The particle nature of The particle nature of mattermatter

The primary particle in chemistry is the atom The primary particle in chemistry is the atom Atoms Atoms are defined as the smallest particle of an elementare defined as the smallest particle of an element However you probably know that there is a However you probably know that there is a substructure to an atom that it is made of substructure to an atom that it is made of protons protons neutrons and electronsneutrons and electrons You may also know that You may also know that protons and neutrons are each made of three protons and neutrons are each made of three quarksquarks

The particle nature of The particle nature of mattermatter

Each element has a Each element has a distinctive atomic distinctive atomic number and mass number and mass numbernumber

The The atomic numberatomic number (Z) (Z) corresponds to the corresponds to the number of protons in number of protons in the nucleusthe nucleus

The The mass numbermass number (A) (A) corresponds to the total corresponds to the total number of neutrons and number of neutrons and protons in the nucleusprotons in the nucleus

Mathematically

A = Z + number of neutrons

Structure of the AtomStructure of the Atom

The particles that make up the elements are The particles that make up the elements are called atoms All atoms of one element are the called atoms All atoms of one element are the same but they are different from the atoms of same but they are different from the atoms of all other elements In other words each all other elements In other words each element has a distinct type of atom with a element has a distinct type of atom with a specific number of protons neutrons and specific number of protons neutrons and electronselectrons

Protons have a +ve chargeProtons have a +ve charge Electrons have a ndashve charge Electrons have a ndashve charge Neutrons have no chargeNeutrons have no charge

Structure of the AtomStructure of the Atom

Protons (p) and Protons (p) and neutrons (n)neutrons (n) are are found in the centre of found in the centre of the atom in the the atom in the nucleus nucleus

Electrons (e)Electrons (e) are are found in the found in the surrounding space surrounding space around the nucleus around the nucleus moving randomly in moving randomly in what is known as an what is known as an lsquolsquoelectron cloudelectron cloudrsquorsquo

RelatiRelative ve massmass

RelatiRelative ve chargchargee

electrelectronon

(e)(e)

1200120000

-1-1

protonproton

(p)(p)11 +1+1

neutroneutronn

(n)(n)11 00

Structure of the AtomStructure of the Atom

IsotopesIsotopesAll atoms of the same All atoms of the same

element have the same element have the same number of protons in number of protons in the nucleus however the nucleus however they do not necessarily they do not necessarily have the same mass have the same mass These atoms differ in These atoms differ in the number of neutrons the number of neutrons and therefore the mass and therefore the mass number and are known number and are known as isotopes Some well-as isotopes Some well-known isotopes are in known isotopes are in the table to the rightthe table to the right

NameName pp

nn

ee

Hydrogen Hydrogen 11 00 11

DeuteriuDeuteriumm

11 11 11

TritiumTritium 11 22 11

Carbon Carbon 1212

66 66 66

Carbon Carbon 1313

66 77 66

Carbon Carbon 1414

66 88 66

Uranium Uranium 235235

9292 141433

9292

Uranium Uranium 238238

9292 141466

9292

Structure of the AtomStructure of the AtomThe Bohr ModelThe Bohr ModelBohrrsquos model of the atom Bohrrsquos model of the atom

consists of electrons in consists of electrons in distinct energy levels or distinct energy levels or lsquoshellsrsquo The shells closest to lsquoshellsrsquo The shells closest to the nucleus are the lowest the nucleus are the lowest energy (n=1) and lsquofillrsquo firstenergy (n=1) and lsquofillrsquo first

The maximum number of The maximum number of electrons in each shell can be electrons in each shell can be calculated by calculated by 2n2n22

ThereforeThereforen=1 maximum of 2 en=1 maximum of 2 en=2 maximum of 8 en=2 maximum of 8 en=3 maximum of 18 en=3 maximum of 18 eand so onhellipand so onhellip

The valence shell or outer shell The valence shell or outer shell can hold a maximum of 8can hold a maximum of 8

Structure of the AtomStructure of the AtomOrbitalsOrbitalsSchroumldinger used quantum mechanics to describe the shape Schroumldinger used quantum mechanics to describe the shape

of the lsquocloudsrsquo within each energy level These are called of the lsquocloudsrsquo within each energy level These are called orbitals and each energy level contains an increasing orbitals and each energy level contains an increasing number of orbitals to accommodate more electrons All number of orbitals to accommodate more electrons All energy levels contain lsquosrsquo orbitals which are spherical (one energy levels contain lsquosrsquo orbitals which are spherical (one lobe) All but the first energy level contain 3 lsquoprsquo orbitals lobe) All but the first energy level contain 3 lsquoprsquo orbitals which are dumbbell shaped (two lobes) After the first two which are dumbbell shaped (two lobes) After the first two each energy level contains 5 lsquodrsquo orbitals most of which each energy level contains 5 lsquodrsquo orbitals most of which have 4 lobes Higher energy levels contain 7 lsquofrsquo orbitals have 4 lobes Higher energy levels contain 7 lsquofrsquo orbitals Each orbital can accommodate 2 electrons ThereforeEach orbital can accommodate 2 electrons Therefore

lsquolsquosrsquo orbitals hold 2 electronssrsquo orbitals hold 2 electrons lsquolsquoprsquo orbitals hold 6 electronsprsquo orbitals hold 6 electrons lsquolsquodrsquo orbitals hold 10 electronsdrsquo orbitals hold 10 electrons lsquolsquofrsquo orbitals hold 14 electronsfrsquo orbitals hold 14 electrons

httpwebfac1enmuedulongrowwworbitalsatorbhtmNote For Interest Only You are not required to learn this information for the HSC

The particle nature of The particle nature of mattermatter

Matter is often described as being made up of small particles that Matter is often described as being made up of small particles that are continuously moving and interacting In each of the three states are continuously moving and interacting In each of the three states of matter (solid liquid gas) the particles experience vibrational of matter (solid liquid gas) the particles experience vibrational motion Liquids and gases experience translational (movement) motion Liquids and gases experience translational (movement) motion as well Gases experience more translational motion than motion as well Gases experience more translational motion than liquids as they have more energyliquids as they have more energy

liquid gassolid

The particle nature of The particle nature of mattermatter

The primary particle in chemistry is the atom The primary particle in chemistry is the atom Atoms Atoms are defined as the smallest particle of an elementare defined as the smallest particle of an element However you probably know that there is a However you probably know that there is a substructure to an atom that it is made of substructure to an atom that it is made of protons protons neutrons and electronsneutrons and electrons You may also know that You may also know that protons and neutrons are each made of three protons and neutrons are each made of three quarksquarks

The particle nature of The particle nature of mattermatter

Each element has a Each element has a distinctive atomic distinctive atomic number and mass number and mass numbernumber

The The atomic numberatomic number (Z) (Z) corresponds to the corresponds to the number of protons in number of protons in the nucleusthe nucleus

The The mass numbermass number (A) (A) corresponds to the total corresponds to the total number of neutrons and number of neutrons and protons in the nucleusprotons in the nucleus

Mathematically

A = Z + number of neutrons

Structure of the AtomStructure of the Atom

The particles that make up the elements are The particles that make up the elements are called atoms All atoms of one element are the called atoms All atoms of one element are the same but they are different from the atoms of same but they are different from the atoms of all other elements In other words each all other elements In other words each element has a distinct type of atom with a element has a distinct type of atom with a specific number of protons neutrons and specific number of protons neutrons and electronselectrons

Protons have a +ve chargeProtons have a +ve charge Electrons have a ndashve charge Electrons have a ndashve charge Neutrons have no chargeNeutrons have no charge

Structure of the AtomStructure of the Atom

Protons (p) and Protons (p) and neutrons (n)neutrons (n) are are found in the centre of found in the centre of the atom in the the atom in the nucleus nucleus

Electrons (e)Electrons (e) are are found in the found in the surrounding space surrounding space around the nucleus around the nucleus moving randomly in moving randomly in what is known as an what is known as an lsquolsquoelectron cloudelectron cloudrsquorsquo

RelatiRelative ve massmass

RelatiRelative ve chargchargee

electrelectronon

(e)(e)

1200120000

-1-1

protonproton

(p)(p)11 +1+1

neutroneutronn

(n)(n)11 00

Structure of the AtomStructure of the Atom

IsotopesIsotopesAll atoms of the same All atoms of the same

element have the same element have the same number of protons in number of protons in the nucleus however the nucleus however they do not necessarily they do not necessarily have the same mass have the same mass These atoms differ in These atoms differ in the number of neutrons the number of neutrons and therefore the mass and therefore the mass number and are known number and are known as isotopes Some well-as isotopes Some well-known isotopes are in known isotopes are in the table to the rightthe table to the right

NameName pp

nn

ee

Hydrogen Hydrogen 11 00 11

DeuteriuDeuteriumm

11 11 11

TritiumTritium 11 22 11

Carbon Carbon 1212

66 66 66

Carbon Carbon 1313

66 77 66

Carbon Carbon 1414

66 88 66

Uranium Uranium 235235

9292 141433

9292

Uranium Uranium 238238

9292 141466

9292

Structure of the AtomStructure of the AtomThe Bohr ModelThe Bohr ModelBohrrsquos model of the atom Bohrrsquos model of the atom

consists of electrons in consists of electrons in distinct energy levels or distinct energy levels or lsquoshellsrsquo The shells closest to lsquoshellsrsquo The shells closest to the nucleus are the lowest the nucleus are the lowest energy (n=1) and lsquofillrsquo firstenergy (n=1) and lsquofillrsquo first

The maximum number of The maximum number of electrons in each shell can be electrons in each shell can be calculated by calculated by 2n2n22

ThereforeThereforen=1 maximum of 2 en=1 maximum of 2 en=2 maximum of 8 en=2 maximum of 8 en=3 maximum of 18 en=3 maximum of 18 eand so onhellipand so onhellip

The valence shell or outer shell The valence shell or outer shell can hold a maximum of 8can hold a maximum of 8

Structure of the AtomStructure of the AtomOrbitalsOrbitalsSchroumldinger used quantum mechanics to describe the shape Schroumldinger used quantum mechanics to describe the shape

of the lsquocloudsrsquo within each energy level These are called of the lsquocloudsrsquo within each energy level These are called orbitals and each energy level contains an increasing orbitals and each energy level contains an increasing number of orbitals to accommodate more electrons All number of orbitals to accommodate more electrons All energy levels contain lsquosrsquo orbitals which are spherical (one energy levels contain lsquosrsquo orbitals which are spherical (one lobe) All but the first energy level contain 3 lsquoprsquo orbitals lobe) All but the first energy level contain 3 lsquoprsquo orbitals which are dumbbell shaped (two lobes) After the first two which are dumbbell shaped (two lobes) After the first two each energy level contains 5 lsquodrsquo orbitals most of which each energy level contains 5 lsquodrsquo orbitals most of which have 4 lobes Higher energy levels contain 7 lsquofrsquo orbitals have 4 lobes Higher energy levels contain 7 lsquofrsquo orbitals Each orbital can accommodate 2 electrons ThereforeEach orbital can accommodate 2 electrons Therefore

lsquolsquosrsquo orbitals hold 2 electronssrsquo orbitals hold 2 electrons lsquolsquoprsquo orbitals hold 6 electronsprsquo orbitals hold 6 electrons lsquolsquodrsquo orbitals hold 10 electronsdrsquo orbitals hold 10 electrons lsquolsquofrsquo orbitals hold 14 electronsfrsquo orbitals hold 14 electrons

httpwebfac1enmuedulongrowwworbitalsatorbhtmNote For Interest Only You are not required to learn this information for the HSC

The particle nature of The particle nature of mattermatter

The primary particle in chemistry is the atom The primary particle in chemistry is the atom Atoms Atoms are defined as the smallest particle of an elementare defined as the smallest particle of an element However you probably know that there is a However you probably know that there is a substructure to an atom that it is made of substructure to an atom that it is made of protons protons neutrons and electronsneutrons and electrons You may also know that You may also know that protons and neutrons are each made of three protons and neutrons are each made of three quarksquarks

The particle nature of The particle nature of mattermatter

Each element has a Each element has a distinctive atomic distinctive atomic number and mass number and mass numbernumber

The The atomic numberatomic number (Z) (Z) corresponds to the corresponds to the number of protons in number of protons in the nucleusthe nucleus

The The mass numbermass number (A) (A) corresponds to the total corresponds to the total number of neutrons and number of neutrons and protons in the nucleusprotons in the nucleus

Mathematically

A = Z + number of neutrons

Structure of the AtomStructure of the Atom

The particles that make up the elements are The particles that make up the elements are called atoms All atoms of one element are the called atoms All atoms of one element are the same but they are different from the atoms of same but they are different from the atoms of all other elements In other words each all other elements In other words each element has a distinct type of atom with a element has a distinct type of atom with a specific number of protons neutrons and specific number of protons neutrons and electronselectrons

Protons have a +ve chargeProtons have a +ve charge Electrons have a ndashve charge Electrons have a ndashve charge Neutrons have no chargeNeutrons have no charge

Structure of the AtomStructure of the Atom

Protons (p) and Protons (p) and neutrons (n)neutrons (n) are are found in the centre of found in the centre of the atom in the the atom in the nucleus nucleus

Electrons (e)Electrons (e) are are found in the found in the surrounding space surrounding space around the nucleus around the nucleus moving randomly in moving randomly in what is known as an what is known as an lsquolsquoelectron cloudelectron cloudrsquorsquo

RelatiRelative ve massmass

RelatiRelative ve chargchargee

electrelectronon

(e)(e)

1200120000

-1-1

protonproton

(p)(p)11 +1+1

neutroneutronn

(n)(n)11 00

Structure of the AtomStructure of the Atom

IsotopesIsotopesAll atoms of the same All atoms of the same

element have the same element have the same number of protons in number of protons in the nucleus however the nucleus however they do not necessarily they do not necessarily have the same mass have the same mass These atoms differ in These atoms differ in the number of neutrons the number of neutrons and therefore the mass and therefore the mass number and are known number and are known as isotopes Some well-as isotopes Some well-known isotopes are in known isotopes are in the table to the rightthe table to the right

NameName pp

nn

ee

Hydrogen Hydrogen 11 00 11

DeuteriuDeuteriumm

11 11 11

TritiumTritium 11 22 11

Carbon Carbon 1212

66 66 66

Carbon Carbon 1313

66 77 66

Carbon Carbon 1414

66 88 66

Uranium Uranium 235235

9292 141433

9292

Uranium Uranium 238238

9292 141466

9292

Structure of the AtomStructure of the AtomThe Bohr ModelThe Bohr ModelBohrrsquos model of the atom Bohrrsquos model of the atom

consists of electrons in consists of electrons in distinct energy levels or distinct energy levels or lsquoshellsrsquo The shells closest to lsquoshellsrsquo The shells closest to the nucleus are the lowest the nucleus are the lowest energy (n=1) and lsquofillrsquo firstenergy (n=1) and lsquofillrsquo first

The maximum number of The maximum number of electrons in each shell can be electrons in each shell can be calculated by calculated by 2n2n22

ThereforeThereforen=1 maximum of 2 en=1 maximum of 2 en=2 maximum of 8 en=2 maximum of 8 en=3 maximum of 18 en=3 maximum of 18 eand so onhellipand so onhellip

The valence shell or outer shell The valence shell or outer shell can hold a maximum of 8can hold a maximum of 8

Structure of the AtomStructure of the AtomOrbitalsOrbitalsSchroumldinger used quantum mechanics to describe the shape Schroumldinger used quantum mechanics to describe the shape

of the lsquocloudsrsquo within each energy level These are called of the lsquocloudsrsquo within each energy level These are called orbitals and each energy level contains an increasing orbitals and each energy level contains an increasing number of orbitals to accommodate more electrons All number of orbitals to accommodate more electrons All energy levels contain lsquosrsquo orbitals which are spherical (one energy levels contain lsquosrsquo orbitals which are spherical (one lobe) All but the first energy level contain 3 lsquoprsquo orbitals lobe) All but the first energy level contain 3 lsquoprsquo orbitals which are dumbbell shaped (two lobes) After the first two which are dumbbell shaped (two lobes) After the first two each energy level contains 5 lsquodrsquo orbitals most of which each energy level contains 5 lsquodrsquo orbitals most of which have 4 lobes Higher energy levels contain 7 lsquofrsquo orbitals have 4 lobes Higher energy levels contain 7 lsquofrsquo orbitals Each orbital can accommodate 2 electrons ThereforeEach orbital can accommodate 2 electrons Therefore

lsquolsquosrsquo orbitals hold 2 electronssrsquo orbitals hold 2 electrons lsquolsquoprsquo orbitals hold 6 electronsprsquo orbitals hold 6 electrons lsquolsquodrsquo orbitals hold 10 electronsdrsquo orbitals hold 10 electrons lsquolsquofrsquo orbitals hold 14 electronsfrsquo orbitals hold 14 electrons

httpwebfac1enmuedulongrowwworbitalsatorbhtmNote For Interest Only You are not required to learn this information for the HSC

The particle nature of The particle nature of mattermatter

Each element has a Each element has a distinctive atomic distinctive atomic number and mass number and mass numbernumber

The The atomic numberatomic number (Z) (Z) corresponds to the corresponds to the number of protons in number of protons in the nucleusthe nucleus

The The mass numbermass number (A) (A) corresponds to the total corresponds to the total number of neutrons and number of neutrons and protons in the nucleusprotons in the nucleus

Mathematically

A = Z + number of neutrons

Structure of the AtomStructure of the Atom

The particles that make up the elements are The particles that make up the elements are called atoms All atoms of one element are the called atoms All atoms of one element are the same but they are different from the atoms of same but they are different from the atoms of all other elements In other words each all other elements In other words each element has a distinct type of atom with a element has a distinct type of atom with a specific number of protons neutrons and specific number of protons neutrons and electronselectrons

Protons have a +ve chargeProtons have a +ve charge Electrons have a ndashve charge Electrons have a ndashve charge Neutrons have no chargeNeutrons have no charge

Structure of the AtomStructure of the Atom

Protons (p) and Protons (p) and neutrons (n)neutrons (n) are are found in the centre of found in the centre of the atom in the the atom in the nucleus nucleus

Electrons (e)Electrons (e) are are found in the found in the surrounding space surrounding space around the nucleus around the nucleus moving randomly in moving randomly in what is known as an what is known as an lsquolsquoelectron cloudelectron cloudrsquorsquo

RelatiRelative ve massmass

RelatiRelative ve chargchargee

electrelectronon

(e)(e)

1200120000

-1-1

protonproton

(p)(p)11 +1+1

neutroneutronn

(n)(n)11 00

Structure of the AtomStructure of the Atom

IsotopesIsotopesAll atoms of the same All atoms of the same

element have the same element have the same number of protons in number of protons in the nucleus however the nucleus however they do not necessarily they do not necessarily have the same mass have the same mass These atoms differ in These atoms differ in the number of neutrons the number of neutrons and therefore the mass and therefore the mass number and are known number and are known as isotopes Some well-as isotopes Some well-known isotopes are in known isotopes are in the table to the rightthe table to the right

NameName pp

nn

ee

Hydrogen Hydrogen 11 00 11

DeuteriuDeuteriumm

11 11 11

TritiumTritium 11 22 11

Carbon Carbon 1212

66 66 66

Carbon Carbon 1313

66 77 66

Carbon Carbon 1414

66 88 66

Uranium Uranium 235235

9292 141433

9292

Uranium Uranium 238238

9292 141466

9292

Structure of the AtomStructure of the AtomThe Bohr ModelThe Bohr ModelBohrrsquos model of the atom Bohrrsquos model of the atom

consists of electrons in consists of electrons in distinct energy levels or distinct energy levels or lsquoshellsrsquo The shells closest to lsquoshellsrsquo The shells closest to the nucleus are the lowest the nucleus are the lowest energy (n=1) and lsquofillrsquo firstenergy (n=1) and lsquofillrsquo first

The maximum number of The maximum number of electrons in each shell can be electrons in each shell can be calculated by calculated by 2n2n22

ThereforeThereforen=1 maximum of 2 en=1 maximum of 2 en=2 maximum of 8 en=2 maximum of 8 en=3 maximum of 18 en=3 maximum of 18 eand so onhellipand so onhellip

The valence shell or outer shell The valence shell or outer shell can hold a maximum of 8can hold a maximum of 8

Structure of the AtomStructure of the AtomOrbitalsOrbitalsSchroumldinger used quantum mechanics to describe the shape Schroumldinger used quantum mechanics to describe the shape

of the lsquocloudsrsquo within each energy level These are called of the lsquocloudsrsquo within each energy level These are called orbitals and each energy level contains an increasing orbitals and each energy level contains an increasing number of orbitals to accommodate more electrons All number of orbitals to accommodate more electrons All energy levels contain lsquosrsquo orbitals which are spherical (one energy levels contain lsquosrsquo orbitals which are spherical (one lobe) All but the first energy level contain 3 lsquoprsquo orbitals lobe) All but the first energy level contain 3 lsquoprsquo orbitals which are dumbbell shaped (two lobes) After the first two which are dumbbell shaped (two lobes) After the first two each energy level contains 5 lsquodrsquo orbitals most of which each energy level contains 5 lsquodrsquo orbitals most of which have 4 lobes Higher energy levels contain 7 lsquofrsquo orbitals have 4 lobes Higher energy levels contain 7 lsquofrsquo orbitals Each orbital can accommodate 2 electrons ThereforeEach orbital can accommodate 2 electrons Therefore

lsquolsquosrsquo orbitals hold 2 electronssrsquo orbitals hold 2 electrons lsquolsquoprsquo orbitals hold 6 electronsprsquo orbitals hold 6 electrons lsquolsquodrsquo orbitals hold 10 electronsdrsquo orbitals hold 10 electrons lsquolsquofrsquo orbitals hold 14 electronsfrsquo orbitals hold 14 electrons

httpwebfac1enmuedulongrowwworbitalsatorbhtmNote For Interest Only You are not required to learn this information for the HSC

Structure of the AtomStructure of the Atom

The particles that make up the elements are The particles that make up the elements are called atoms All atoms of one element are the called atoms All atoms of one element are the same but they are different from the atoms of same but they are different from the atoms of all other elements In other words each all other elements In other words each element has a distinct type of atom with a element has a distinct type of atom with a specific number of protons neutrons and specific number of protons neutrons and electronselectrons

Protons have a +ve chargeProtons have a +ve charge Electrons have a ndashve charge Electrons have a ndashve charge Neutrons have no chargeNeutrons have no charge

Structure of the AtomStructure of the Atom

Protons (p) and Protons (p) and neutrons (n)neutrons (n) are are found in the centre of found in the centre of the atom in the the atom in the nucleus nucleus

Electrons (e)Electrons (e) are are found in the found in the surrounding space surrounding space around the nucleus around the nucleus moving randomly in moving randomly in what is known as an what is known as an lsquolsquoelectron cloudelectron cloudrsquorsquo

RelatiRelative ve massmass

RelatiRelative ve chargchargee

electrelectronon

(e)(e)

1200120000

-1-1

protonproton

(p)(p)11 +1+1

neutroneutronn

(n)(n)11 00

Structure of the AtomStructure of the Atom

IsotopesIsotopesAll atoms of the same All atoms of the same

element have the same element have the same number of protons in number of protons in the nucleus however the nucleus however they do not necessarily they do not necessarily have the same mass have the same mass These atoms differ in These atoms differ in the number of neutrons the number of neutrons and therefore the mass and therefore the mass number and are known number and are known as isotopes Some well-as isotopes Some well-known isotopes are in known isotopes are in the table to the rightthe table to the right

NameName pp

nn

ee

Hydrogen Hydrogen 11 00 11

DeuteriuDeuteriumm

11 11 11

TritiumTritium 11 22 11

Carbon Carbon 1212

66 66 66

Carbon Carbon 1313

66 77 66

Carbon Carbon 1414

66 88 66

Uranium Uranium 235235

9292 141433

9292

Uranium Uranium 238238

9292 141466

9292

Structure of the AtomStructure of the AtomThe Bohr ModelThe Bohr ModelBohrrsquos model of the atom Bohrrsquos model of the atom

consists of electrons in consists of electrons in distinct energy levels or distinct energy levels or lsquoshellsrsquo The shells closest to lsquoshellsrsquo The shells closest to the nucleus are the lowest the nucleus are the lowest energy (n=1) and lsquofillrsquo firstenergy (n=1) and lsquofillrsquo first

The maximum number of The maximum number of electrons in each shell can be electrons in each shell can be calculated by calculated by 2n2n22

ThereforeThereforen=1 maximum of 2 en=1 maximum of 2 en=2 maximum of 8 en=2 maximum of 8 en=3 maximum of 18 en=3 maximum of 18 eand so onhellipand so onhellip

The valence shell or outer shell The valence shell or outer shell can hold a maximum of 8can hold a maximum of 8

Structure of the AtomStructure of the AtomOrbitalsOrbitalsSchroumldinger used quantum mechanics to describe the shape Schroumldinger used quantum mechanics to describe the shape

of the lsquocloudsrsquo within each energy level These are called of the lsquocloudsrsquo within each energy level These are called orbitals and each energy level contains an increasing orbitals and each energy level contains an increasing number of orbitals to accommodate more electrons All number of orbitals to accommodate more electrons All energy levels contain lsquosrsquo orbitals which are spherical (one energy levels contain lsquosrsquo orbitals which are spherical (one lobe) All but the first energy level contain 3 lsquoprsquo orbitals lobe) All but the first energy level contain 3 lsquoprsquo orbitals which are dumbbell shaped (two lobes) After the first two which are dumbbell shaped (two lobes) After the first two each energy level contains 5 lsquodrsquo orbitals most of which each energy level contains 5 lsquodrsquo orbitals most of which have 4 lobes Higher energy levels contain 7 lsquofrsquo orbitals have 4 lobes Higher energy levels contain 7 lsquofrsquo orbitals Each orbital can accommodate 2 electrons ThereforeEach orbital can accommodate 2 electrons Therefore

lsquolsquosrsquo orbitals hold 2 electronssrsquo orbitals hold 2 electrons lsquolsquoprsquo orbitals hold 6 electronsprsquo orbitals hold 6 electrons lsquolsquodrsquo orbitals hold 10 electronsdrsquo orbitals hold 10 electrons lsquolsquofrsquo orbitals hold 14 electronsfrsquo orbitals hold 14 electrons

httpwebfac1enmuedulongrowwworbitalsatorbhtmNote For Interest Only You are not required to learn this information for the HSC

Structure of the AtomStructure of the Atom

Protons (p) and Protons (p) and neutrons (n)neutrons (n) are are found in the centre of found in the centre of the atom in the the atom in the nucleus nucleus

Electrons (e)Electrons (e) are are found in the found in the surrounding space surrounding space around the nucleus around the nucleus moving randomly in moving randomly in what is known as an what is known as an lsquolsquoelectron cloudelectron cloudrsquorsquo

RelatiRelative ve massmass

RelatiRelative ve chargchargee

electrelectronon

(e)(e)

1200120000

-1-1

protonproton

(p)(p)11 +1+1

neutroneutronn

(n)(n)11 00

Structure of the AtomStructure of the Atom

IsotopesIsotopesAll atoms of the same All atoms of the same

element have the same element have the same number of protons in number of protons in the nucleus however the nucleus however they do not necessarily they do not necessarily have the same mass have the same mass These atoms differ in These atoms differ in the number of neutrons the number of neutrons and therefore the mass and therefore the mass number and are known number and are known as isotopes Some well-as isotopes Some well-known isotopes are in known isotopes are in the table to the rightthe table to the right

NameName pp

nn

ee

Hydrogen Hydrogen 11 00 11

DeuteriuDeuteriumm

11 11 11

TritiumTritium 11 22 11

Carbon Carbon 1212

66 66 66

Carbon Carbon 1313

66 77 66

Carbon Carbon 1414

66 88 66

Uranium Uranium 235235

9292 141433

9292

Uranium Uranium 238238

9292 141466

9292

Structure of the AtomStructure of the AtomThe Bohr ModelThe Bohr ModelBohrrsquos model of the atom Bohrrsquos model of the atom

consists of electrons in consists of electrons in distinct energy levels or distinct energy levels or lsquoshellsrsquo The shells closest to lsquoshellsrsquo The shells closest to the nucleus are the lowest the nucleus are the lowest energy (n=1) and lsquofillrsquo firstenergy (n=1) and lsquofillrsquo first

The maximum number of The maximum number of electrons in each shell can be electrons in each shell can be calculated by calculated by 2n2n22

ThereforeThereforen=1 maximum of 2 en=1 maximum of 2 en=2 maximum of 8 en=2 maximum of 8 en=3 maximum of 18 en=3 maximum of 18 eand so onhellipand so onhellip

The valence shell or outer shell The valence shell or outer shell can hold a maximum of 8can hold a maximum of 8

Structure of the AtomStructure of the AtomOrbitalsOrbitalsSchroumldinger used quantum mechanics to describe the shape Schroumldinger used quantum mechanics to describe the shape

of the lsquocloudsrsquo within each energy level These are called of the lsquocloudsrsquo within each energy level These are called orbitals and each energy level contains an increasing orbitals and each energy level contains an increasing number of orbitals to accommodate more electrons All number of orbitals to accommodate more electrons All energy levels contain lsquosrsquo orbitals which are spherical (one energy levels contain lsquosrsquo orbitals which are spherical (one lobe) All but the first energy level contain 3 lsquoprsquo orbitals lobe) All but the first energy level contain 3 lsquoprsquo orbitals which are dumbbell shaped (two lobes) After the first two which are dumbbell shaped (two lobes) After the first two each energy level contains 5 lsquodrsquo orbitals most of which each energy level contains 5 lsquodrsquo orbitals most of which have 4 lobes Higher energy levels contain 7 lsquofrsquo orbitals have 4 lobes Higher energy levels contain 7 lsquofrsquo orbitals Each orbital can accommodate 2 electrons ThereforeEach orbital can accommodate 2 electrons Therefore

lsquolsquosrsquo orbitals hold 2 electronssrsquo orbitals hold 2 electrons lsquolsquoprsquo orbitals hold 6 electronsprsquo orbitals hold 6 electrons lsquolsquodrsquo orbitals hold 10 electronsdrsquo orbitals hold 10 electrons lsquolsquofrsquo orbitals hold 14 electronsfrsquo orbitals hold 14 electrons

httpwebfac1enmuedulongrowwworbitalsatorbhtmNote For Interest Only You are not required to learn this information for the HSC

Structure of the AtomStructure of the Atom

IsotopesIsotopesAll atoms of the same All atoms of the same

element have the same element have the same number of protons in number of protons in the nucleus however the nucleus however they do not necessarily they do not necessarily have the same mass have the same mass These atoms differ in These atoms differ in the number of neutrons the number of neutrons and therefore the mass and therefore the mass number and are known number and are known as isotopes Some well-as isotopes Some well-known isotopes are in known isotopes are in the table to the rightthe table to the right

NameName pp

nn

ee

Hydrogen Hydrogen 11 00 11

DeuteriuDeuteriumm

11 11 11

TritiumTritium 11 22 11

Carbon Carbon 1212

66 66 66

Carbon Carbon 1313

66 77 66

Carbon Carbon 1414

66 88 66

Uranium Uranium 235235

9292 141433

9292

Uranium Uranium 238238

9292 141466

9292

Structure of the AtomStructure of the AtomThe Bohr ModelThe Bohr ModelBohrrsquos model of the atom Bohrrsquos model of the atom

consists of electrons in consists of electrons in distinct energy levels or distinct energy levels or lsquoshellsrsquo The shells closest to lsquoshellsrsquo The shells closest to the nucleus are the lowest the nucleus are the lowest energy (n=1) and lsquofillrsquo firstenergy (n=1) and lsquofillrsquo first

The maximum number of The maximum number of electrons in each shell can be electrons in each shell can be calculated by calculated by 2n2n22

ThereforeThereforen=1 maximum of 2 en=1 maximum of 2 en=2 maximum of 8 en=2 maximum of 8 en=3 maximum of 18 en=3 maximum of 18 eand so onhellipand so onhellip

The valence shell or outer shell The valence shell or outer shell can hold a maximum of 8can hold a maximum of 8

Structure of the AtomStructure of the AtomOrbitalsOrbitalsSchroumldinger used quantum mechanics to describe the shape Schroumldinger used quantum mechanics to describe the shape

of the lsquocloudsrsquo within each energy level These are called of the lsquocloudsrsquo within each energy level These are called orbitals and each energy level contains an increasing orbitals and each energy level contains an increasing number of orbitals to accommodate more electrons All number of orbitals to accommodate more electrons All energy levels contain lsquosrsquo orbitals which are spherical (one energy levels contain lsquosrsquo orbitals which are spherical (one lobe) All but the first energy level contain 3 lsquoprsquo orbitals lobe) All but the first energy level contain 3 lsquoprsquo orbitals which are dumbbell shaped (two lobes) After the first two which are dumbbell shaped (two lobes) After the first two each energy level contains 5 lsquodrsquo orbitals most of which each energy level contains 5 lsquodrsquo orbitals most of which have 4 lobes Higher energy levels contain 7 lsquofrsquo orbitals have 4 lobes Higher energy levels contain 7 lsquofrsquo orbitals Each orbital can accommodate 2 electrons ThereforeEach orbital can accommodate 2 electrons Therefore

lsquolsquosrsquo orbitals hold 2 electronssrsquo orbitals hold 2 electrons lsquolsquoprsquo orbitals hold 6 electronsprsquo orbitals hold 6 electrons lsquolsquodrsquo orbitals hold 10 electronsdrsquo orbitals hold 10 electrons lsquolsquofrsquo orbitals hold 14 electronsfrsquo orbitals hold 14 electrons

httpwebfac1enmuedulongrowwworbitalsatorbhtmNote For Interest Only You are not required to learn this information for the HSC

Structure of the AtomStructure of the AtomThe Bohr ModelThe Bohr ModelBohrrsquos model of the atom Bohrrsquos model of the atom

consists of electrons in consists of electrons in distinct energy levels or distinct energy levels or lsquoshellsrsquo The shells closest to lsquoshellsrsquo The shells closest to the nucleus are the lowest the nucleus are the lowest energy (n=1) and lsquofillrsquo firstenergy (n=1) and lsquofillrsquo first

The maximum number of The maximum number of electrons in each shell can be electrons in each shell can be calculated by calculated by 2n2n22

ThereforeThereforen=1 maximum of 2 en=1 maximum of 2 en=2 maximum of 8 en=2 maximum of 8 en=3 maximum of 18 en=3 maximum of 18 eand so onhellipand so onhellip

The valence shell or outer shell The valence shell or outer shell can hold a maximum of 8can hold a maximum of 8

Structure of the AtomStructure of the AtomOrbitalsOrbitalsSchroumldinger used quantum mechanics to describe the shape Schroumldinger used quantum mechanics to describe the shape

of the lsquocloudsrsquo within each energy level These are called of the lsquocloudsrsquo within each energy level These are called orbitals and each energy level contains an increasing orbitals and each energy level contains an increasing number of orbitals to accommodate more electrons All number of orbitals to accommodate more electrons All energy levels contain lsquosrsquo orbitals which are spherical (one energy levels contain lsquosrsquo orbitals which are spherical (one lobe) All but the first energy level contain 3 lsquoprsquo orbitals lobe) All but the first energy level contain 3 lsquoprsquo orbitals which are dumbbell shaped (two lobes) After the first two which are dumbbell shaped (two lobes) After the first two each energy level contains 5 lsquodrsquo orbitals most of which each energy level contains 5 lsquodrsquo orbitals most of which have 4 lobes Higher energy levels contain 7 lsquofrsquo orbitals have 4 lobes Higher energy levels contain 7 lsquofrsquo orbitals Each orbital can accommodate 2 electrons ThereforeEach orbital can accommodate 2 electrons Therefore

lsquolsquosrsquo orbitals hold 2 electronssrsquo orbitals hold 2 electrons lsquolsquoprsquo orbitals hold 6 electronsprsquo orbitals hold 6 electrons lsquolsquodrsquo orbitals hold 10 electronsdrsquo orbitals hold 10 electrons lsquolsquofrsquo orbitals hold 14 electronsfrsquo orbitals hold 14 electrons

httpwebfac1enmuedulongrowwworbitalsatorbhtmNote For Interest Only You are not required to learn this information for the HSC

Structure of the AtomStructure of the AtomOrbitalsOrbitalsSchroumldinger used quantum mechanics to describe the shape Schroumldinger used quantum mechanics to describe the shape

of the lsquocloudsrsquo within each energy level These are called of the lsquocloudsrsquo within each energy level These are called orbitals and each energy level contains an increasing orbitals and each energy level contains an increasing number of orbitals to accommodate more electrons All number of orbitals to accommodate more electrons All energy levels contain lsquosrsquo orbitals which are spherical (one energy levels contain lsquosrsquo orbitals which are spherical (one lobe) All but the first energy level contain 3 lsquoprsquo orbitals lobe) All but the first energy level contain 3 lsquoprsquo orbitals which are dumbbell shaped (two lobes) After the first two which are dumbbell shaped (two lobes) After the first two each energy level contains 5 lsquodrsquo orbitals most of which each energy level contains 5 lsquodrsquo orbitals most of which have 4 lobes Higher energy levels contain 7 lsquofrsquo orbitals have 4 lobes Higher energy levels contain 7 lsquofrsquo orbitals Each orbital can accommodate 2 electrons ThereforeEach orbital can accommodate 2 electrons Therefore

lsquolsquosrsquo orbitals hold 2 electronssrsquo orbitals hold 2 electrons lsquolsquoprsquo orbitals hold 6 electronsprsquo orbitals hold 6 electrons lsquolsquodrsquo orbitals hold 10 electronsdrsquo orbitals hold 10 electrons lsquolsquofrsquo orbitals hold 14 electronsfrsquo orbitals hold 14 electrons

httpwebfac1enmuedulongrowwworbitalsatorbhtmNote For Interest Only You are not required to learn this information for the HSC

Structure of the AtomStructure of the Atom

Below is a representation of the relative energy Below is a representation of the relative energy levels of electron orbitals and how they appear levels of electron orbitals and how they appear around the nucleusaround the nucleus

Note For Interest Only You are not required to learn this information for the HSC

Ions ndash loss or gain of e-Ions ndash loss or gain of e-

An atom that loses or gains An atom that loses or gains electrons is called an ion electrons is called an ion

There are two typesThere are two types

11 CationsCations (+) have lost electrons (+) have lost electrons making them positively charged (eg making them positively charged (eg MgMg2+2+ loss of 2e-) loss of 2e-)

22 AnionsAnions (-) have gained electrons (-) have gained electrons making them negatively charged (eg making them negatively charged (eg OO2- 2- gain of 2e-)gain of 2e-)

IonsIonsThe loss or gain of e- to form ions is directly related to the number of The loss or gain of e- to form ions is directly related to the number of

valence e- in an atom All atoms have a driving force towards a noble valence e- in an atom All atoms have a driving force towards a noble gas e- configuration as this is the most stable configuration (ie 8 e- gas e- configuration as this is the most stable configuration (ie 8 e- in the valence shell unless we are talking about the 1in the valence shell unless we are talking about the 1stst shell which shell which only holds 2 e- as in He)only holds 2 e- as in He)

We can predict the ions that are formed by atoms by using the Periodic We can predict the ions that are formed by atoms by using the Periodic Table Table The group number (column number) indicates the The group number (column number) indicates the number of e- in the valence shellnumber of e- in the valence shell Therefore Therefore

Group I has one valence e- and will tend to lose 1e- forming a +1 ion and Group I has one valence e- and will tend to lose 1e- forming a +1 ion and Group VII has 7 valence e- and will tend to gain 1e- forming a -1 ion etcGroup VII has 7 valence e- and will tend to gain 1e- forming a -1 ion etc

The transition metals are more difficult to predict as many of these The transition metals are more difficult to predict as many of these elements have a variable e- configuration however these will all lose elements have a variable e- configuration however these will all lose electrons to form positive ionselectrons to form positive ions

In generalIn generalMetals tend to form cations (+) and non-metals tend to form Metals tend to form cations (+) and non-metals tend to form

anions (-)anions (-)

Ionic bondingIonic bondingIonic bonds are formed from the Ionic bonds are formed from the

transfer of electrons from one transfer of electrons from one atom to another As previously atom to another As previously stated this is to obtain an stated this is to obtain an overall noble gas overall noble gas configuration The ratio of configuration The ratio of atoms results in an electrically atoms results in an electrically neutral compoundneutral compound

Because oppositely charged Because oppositely charged particles attract to form these particles attract to form these bonds bonds ionic bonds tend to ionic bonds tend to form between metals and non-form between metals and non-metalsmetals

Note ionic compounds do not Note ionic compounds do not form discreet molecules form discreet molecules rather they tend to form an rather they tend to form an array of anions and cations in array of anions and cations in a fixed ratio which is given in a fixed ratio which is given in the the empirical formula (See empirical formula (See next slide)next slide)

Electrostatic attraction Electrostatic attraction between oppositely between oppositely charged particlescharged particles

+ -cation anion

ExampleExample

MgMg2+2+ + Cl + Cl-- MgCl MgCl22

Ionic bondingIonic bonding

No discreet molecules are formed in ionic No discreet molecules are formed in ionic bonding due to electrostatic forces bonding due to electrostatic forces holding the atoms together More holding the atoms together More information about these and their information about these and their properties in 825properties in 825-- --

-- -- --

--

-- --

---- --++

++

++

++++

++

++

++++++

Covalent BondingCovalent BondingCovalent bonds are formed between two atoms sharing electrons Covalent bonds are formed between two atoms sharing electrons

In covalent bonding there is no electrostatic attraction as in In covalent bonding there is no electrostatic attraction as in ionic bonding Atoms will lsquosharersquo a pair (single bond) or pairs ionic bonding Atoms will lsquosharersquo a pair (single bond) or pairs (double or triple bonds) of e- to gain a noble gas configuration (double or triple bonds) of e- to gain a noble gas configuration For exampleFor example

Cl with and electron configuration of (287) will covalently bond Cl with and electron configuration of (287) will covalently bond with another Cl of (287) or with H of (1) to form Clwith another Cl of (287) or with H of (1) to form Cl22 or HCl or HCl

In the examples of ClIn the examples of Cl22 and HCl all atoms have a full valence and HCl all atoms have a full valence shell due to the sharing of electrons Cl has 8 e- and H has 2 e- shell due to the sharing of electrons Cl has 8 e- and H has 2 e- These compounds then exist as individual particles or molecules These compounds then exist as individual particles or molecules and are known as and are known as covalent molecular substancescovalent molecular substances to distinguish to distinguish them from them from covalent latticescovalent lattices such as in silicon dioxide and such as in silicon dioxide and diamonddiamond

Other examples include water ammonia and carbon dioxideOther examples include water ammonia and carbon dioxide

Covalent BondingCovalent Bonding

Covalent bonding leads to the formation of Covalent bonding leads to the formation of discreet molecules (ie single units that discreet molecules (ie single units that are often weakly bonded together by are often weakly bonded together by intermolecular forcesintermolecular forces) More about these ) More about these and their properties in 825and their properties in 825

WaterWater ChloriChlorinene

HydrogeHydrogen n ChloriChloridede

Lewis Dot StructuresLewis Dot StructuresLewis dot structures are a Lewis dot structures are a

way of representing the way of representing the valence e- configuration valence e- configuration of an atom and show of an atom and show how valence e- are how valence e- are arranged in compoundsarranged in compounds

Lewis dot structures can Lewis dot structures can be used to show the be used to show the formation of ions but are formation of ions but are more commonly used to more commonly used to show covalent bondingshow covalent bonding

The compounds formed to The compounds formed to the right are methane the right are methane ammonia water and ammonia water and hydrogen chloride hydrogen chloride (hydrochloric acid)(hydrochloric acid)

82 The Chemical Earth82 The Chemical Earth

Focus 4Focus 4

Energy is required to extract Energy is required to extract elements from their naturally elements from their naturally

occurring sourcesoccurring sources

Physical vs ChemicalPhysical vs Chemical Physical ndash changes that are associated with Physical ndash changes that are associated with

physical properties which do not change physical properties which do not change the chemical composition of a substancethe chemical composition of a substance Eg hardness density malleability ductility Eg hardness density malleability ductility

electrical and thermal conductivities melting electrical and thermal conductivities melting point boiling point solubilitypoint boiling point solubility

Chemical ndash changes that occur when a Chemical ndash changes that occur when a substance breaks down or reacts with substance breaks down or reacts with another substance in a chemical reactionanother substance in a chemical reaction A new substance is always formed and has A new substance is always formed and has

different properties than the original reactantsdifferent properties than the original reactants

Physical Changes - Physical Changes - examplesexamples

Changing of state (melting iron boiling water)Changing of state (melting iron boiling water) Changing the physical appearance (crushing Changing the physical appearance (crushing

ore in a ball mill drawing copper into wires)ore in a ball mill drawing copper into wires) Dissolving a solid in a liquid (sugar into Dissolving a solid in a liquid (sugar into

water)water) Separation of mixtures (filtering sand from Separation of mixtures (filtering sand from

water separating sea salt from water)water separating sea salt from water)

Physical changes ndash no new substancesPhysical changes ndash no new substances

Chemical Changes - Chemical Changes - indicationsindications

A gas is evolved (iron and HCl generate HA gas is evolved (iron and HCl generate H22 gas) gas) A solid (precipitate) is formed when two A solid (precipitate) is formed when two

solutions are added together (silver nitrate and solutions are added together (silver nitrate and sodium chloride solutions produce a white solid sodium chloride solutions produce a white solid of silver chloride)of silver chloride)

A change in colour (purple potassium A change in colour (purple potassium permanganate (permanganate (KMnO4KMnO4) is added to hydrogen ) is added to hydrogen peroxide the solution turns colourless)peroxide the solution turns colourless)

Change of temperature (magnesium is burned Change of temperature (magnesium is burned in air and becomes very hot)in air and becomes very hot)

Chemical change ndash at least one new Chemical change ndash at least one new substancesubstance

Physical vs Chemical -Physical vs Chemical -WaterWater

Water- a physical Water- a physical changechange

Boiling water is an example Boiling water is an example of relatively weak of relatively weak intermolecular forces intermolecular forces (Hydrogen bonds) (Hydrogen bonds) breakingbreaking

Energy required = 44 kJmolEnergy required = 44 kJmol

Water-a chemical Water-a chemical changechange

Electrolysis of water involves Electrolysis of water involves the breaking of very the breaking of very strong covalent bonds strong covalent bonds between H and O atomsbetween H and O atoms

Energy required = 286 Energy required = 286 kJmolkJmol

Physical vs Chemical -Physical vs Chemical -WaterWater

Boiling ndash breaking H Boiling ndash breaking H bondsbonds

Electrolysis ndash Electrolysis ndash breaking covalent breaking covalent bondsbonds

OOHH

HHHHHH

OOHH

HH

OOHH

HH

OOHH

HH

OOHH

HH

H bondH bond

OO

OO

OOHH

HH

++++

HHHH

Physical vs Chemical -Physical vs Chemical -summarysummary

Chemical changeChemical change

(reaction)(reaction)Physical changePhysical change

At least one new At least one new substance is formedsubstance is formed

No new substances No new substances are formedare formed

Difficult to reverse Difficult to reverse (eg unboiled egg)(eg unboiled egg)

Easily reversed (eg Easily reversed (eg melt ice and freeze it melt ice and freeze it again)again)

Generally requires a Generally requires a large amount of large amount of energyenergy

Generally relatively Generally relatively small quantities of small quantities of energyenergy

Decomposition ReactionsDecomposition Reactions Energy absorbed Energy absorbed

When a compound decomposes into When a compound decomposes into two or more other pure substances two or more other pure substances energy is normally absorbed in the energy is normally absorbed in the form of heat light or electricityform of heat light or electricity

+ AB + AB A + B A + BHeatHeat

LightLight

ElectricityElectricity

Decomposition Reactions-Decomposition Reactions-examplesexamples

HeatHeatSolid Solid copper nitratecopper nitrate decomposes to solid decomposes to solid copper copper

oxideoxide nitrogen dioxidenitrogen dioxide and and oxygenoxygen gases gases

ElectricityElectricityMolten Molten lead bromidelead bromide (400 (40000C) forms C) forms brominebromine gas at gas at

the +ve electrode and liquid the +ve electrode and liquid leadlead at the ndashve at the ndashve electrodeelectrode

LightLightSolid Solid silver chloridesilver chloride decomposes to decomposes to silversilver metal and metal and

chlorinechlorine gas (decomposition of silver compounds gas (decomposition of silver compounds is the basis of photography development)is the basis of photography development)

Synthesis ReactionsSynthesis ReactionsEnergy releasedEnergy released

A synthesis or combination reaction A synthesis or combination reaction involves the combination of two or involves the combination of two or more pure substances When a more pure substances When a compound is formed from its compound is formed from its elements it is known as a elements it is known as a direct direct combination reactioncombination reaction These These reactions normally release energy reactions normally release energy

A + B A + B AB + energy AB + energy

Synthesis reactions - Synthesis reactions - examplesexamples

MagnesiumMagnesium burns in air ( burns in air (oxygenoxygen) to produce ) to produce magnesium oxidemagnesium oxide (light and heat energy (light and heat energy released)released)

HydrogenHydrogen and and oxygenoxygen combine in an combine in an explosive reaction to produce explosive reaction to produce waterwater (much (much energy released)energy released)

CopperCopper metal combines with yellow metal combines with yellow sulphursulphur when heated to produce when heated to produce copper (I) copper (I) sulphidesulphide (much heat energy is released) (much heat energy is released)

Decomposition and Decomposition and SynthesisSynthesis

Everyday ApplicationsEveryday ApplicationsDecompositionDecomposition

Air bags ndash sodium azide Air bags ndash sodium azide (NaN(NaN33) decomposes to ) decomposes to sodium and nitrogen gas by sodium and nitrogen gas by ignition with a detonating ignition with a detonating capcap

Limestone (primarily CaCOLimestone (primarily CaCO33) ) ndash decomposes to calcium ndash decomposes to calcium oxide and carbon dioxide by oxide and carbon dioxide by heating to make lime (CaO) heating to make lime (CaO) cement and glasscement and glass

Aluminium - the industrial Aluminium - the industrial process of electrolysing process of electrolysing aluminium oxide produces aluminium oxide produces aluminium metalaluminium metal

SynthesisSynthesis Rust ndash iron and oxygen Rust ndash iron and oxygen

combine in the presence of combine in the presence of water to form iron (III) oxidewater to form iron (III) oxide

Burning coke (primarily Burning coke (primarily carbon) is used as a fuel in carbon) is used as a fuel in smelting iron ore in a blast smelting iron ore in a blast furnace during the steel furnace during the steel making process making process

Pollutants - NO (nitric oxide Pollutants - NO (nitric oxide or nitrogen monoxide) and or nitrogen monoxide) and NO2 (nitrogen dioxide) are NO2 (nitrogen dioxide) are formed inside the formed inside the combustion chambers of cars combustion chambers of cars from nitrogen and oxygen from nitrogen and oxygen gasesgases

82 The Chemical Earth82 The Chemical Earth

Focus 5Focus 5

The properties of elements and The properties of elements and compounds are determined by compounds are determined by

their bonding and structuretheir bonding and structure

Properties of elements and Properties of elements and their compounds are very their compounds are very

differentdifferent8Fe(s) + S8Fe(s) + S88(s) + heat (s) + heat 8FeS(s) 8FeS(s)

substancsubstancee

colourcolour Melting Melting point point ((00C)C)

Boiling Boiling point point ((00C)C)

Density Density (gcm(gcm33))

magneticmagnetic

IronIron GreyGrey 15351535 27502750 7979 yesyes

SulphurSulphur YellowYellow 113113 445445 2121 nono

Iron (II) Iron (II) sulphidesulphide

Yellow-Yellow-goldgold

11941194 -- 484484 nono

Properties of elements Properties of elements compounds and mixtures compounds and mixtures

are very differentare very differentAluminiumAluminiumPhysical propertiesPhysical properties MP = 660MP = 66000CC Density = 27 gcmDensity = 27 gcm3 3

Conductivity = 378 x10Conductivity = 378 x1066 Smiddotm-1 Smiddotm-1 (20 degC)(20 degC)

Chemical propertiesChemical properties 4Al(s)+ 3O4Al(s)+ 3O22(g) (g) 2Al 2Al22OO33(s)(s) 2Al(s) + 6HCl(g) 2Al(s) + 6HCl(g) 2AlCl 2AlCl33(aq) (aq)

+ 3H+ 3H22(g)(g)

OxygenOxygenPhysical propertiesPhysical properties MP = -219MP = -21900CC Density = 00013 gcmDensity = 00013 gcm33

Conductivity = non-conductorConductivity = non-conductor

Bauxite ore Bauxite ore (Al(Al22OO33xHxH22O)O)Physical propertiesPhysical properties MP = 2045MP = 204500CC Density = 35-4 gcmDensity = 35-4 gcm33

Conductivity = non-conductorConductivity = non-conductor

Chemical propertiesChemical properties AlAl22OO33(s) + 2NaOH + 3H(s) + 2NaOH + 3H22O(l) O(l)

2Na[Al(OH)2Na[Al(OH)44](aq) (Bayer process)](aq) (Bayer process)

NB Bauxite is essentially an impure NB Bauxite is essentially an impure aluminium oxide The major aluminium oxide The major impurities include iron oxides impurities include iron oxides silicon dioxide and titanium silicon dioxide and titanium dioxide The impurities remain as dioxide The impurities remain as solids and do not react with solids and do not react with NaOH This process removes NaOH This process removes these impuritiesthese impurities

Structure of metalsStructure of metals

Metals can be described as three-Metals can be described as three-dimensional lattices of positive ions in a dimensional lattices of positive ions in a sea of delocalised electrons sea of delocalised electrons

Covalent BondingCovalent Bonding Covalent Molecular-strong Covalent Molecular-strong

bonds weak bonds weak intermolecular forces intermolecular forces holding molecules holding molecules togethertogether

Covalent Network-Covalent Network-covalent bonding lattice covalent bonding lattice that extends indefinitely that extends indefinitely throughout the crystalthroughout the crystal

Ionic bondingIonic bonding

No discreet molecules are formed in No discreet molecules are formed in ionic bonding due to electrostatic ionic bonding due to electrostatic forces holding the atoms together forces holding the atoms together They form a continuing 3D latticeThey form a continuing 3D lattice

-- --

-- -- --

--

-- --

---- --++

++

++

++++

++

++

++++++

Properties associated with Properties associated with bond typesbond types

Metallic bondingMetallic bonding High melting pointsHigh melting points-due to strong attraction between -due to strong attraction between

positively charged metal ions and delocalized positively charged metal ions and delocalized electrons The higher the valency the stronger the electrons The higher the valency the stronger the bond eg Cabond eg Ca2+2+ is stronger than K is stronger than K++

Good conductors of heat and electricityGood conductors of heat and electricity-due to the high -due to the high mobility of delocalized electrons Electrons enter and mobility of delocalized electrons Electrons enter and leave a metal easilyleave a metal easily

Malleable and ductileMalleable and ductile-due to delocalized electrons not -due to delocalized electrons not belonging to any particular metal atom Therefore one belonging to any particular metal atom Therefore one layer of ions can slide over another without disrupting layer of ions can slide over another without disrupting the bond between metal atoms The electrons and the bond between metal atoms The electrons and metal ions simply rearrangemetal ions simply rearrange

HardnessHardness- tend to be hard due to tightly packed atoms- tend to be hard due to tightly packed atoms

Properties associated with Properties associated with bond typesbond types

Ionic bondingIonic bonding High melting pointsHigh melting points-due to strong electrostatic attraction -due to strong electrostatic attraction

between anions and cationsbetween anions and cations

Non-conductors of electricity in solid stateNon-conductors of electricity in solid state-due to -due to oppositely charged particles which are in fixed positionsoppositely charged particles which are in fixed positions

Conductors in the liquid (molten) stateConductors in the liquid (molten) state-due to the ions -due to the ions being able to move freely through the liquidbeing able to move freely through the liquid

HardnessHardness-due to strong electrostatic attraction between -due to strong electrostatic attraction between oppositely charged particlesoppositely charged particles

BrittleBrittle-due to the fixed location of oppositely charged -due to the fixed location of oppositely charged particles Displacement of ions moves them closer to ions particles Displacement of ions moves them closer to ions of a similar charge which increases the repulsive forces of a similar charge which increases the repulsive forces along the fracturealong the fracture

Properties associated with Properties associated with bond typesbond types

Covalent molecular bondingCovalent molecular bonding Low melting pointsLow melting points-due to generally weak -due to generally weak

attractive forces between molecules There attractive forces between molecules There are exceptions to this rule (eg Iare exceptions to this rule (eg I22 melts at melts at 11411400C but decomposes at 1000C but decomposes at 100000C) C)

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

SoftSoft-due to weak forces existing between -due to weak forces existing between moleculesmolecules

Properties associated with Properties associated with bond typesbond types

Covalent Network bondingCovalent Network bonding Very high melting points and boiling Very high melting points and boiling

pointspoints-due to strong covalent bonding -due to strong covalent bonding which form rigid 3-D structureswhich form rigid 3-D structures

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

Extremely hardExtremely hard- due to strong covalent - due to strong covalent bonding which form rigid 3-D structuresbonding which form rigid 3-D structures

The Chemical EarthThe Chemical Earth

Compiled by Robert Slider (2006)

Please share this resource with others

Ions ndash loss or gain of e-Ions ndash loss or gain of e-

An atom that loses or gains An atom that loses or gains electrons is called an ion electrons is called an ion

There are two typesThere are two types

11 CationsCations (+) have lost electrons (+) have lost electrons making them positively charged (eg making them positively charged (eg MgMg2+2+ loss of 2e-) loss of 2e-)

22 AnionsAnions (-) have gained electrons (-) have gained electrons making them negatively charged (eg making them negatively charged (eg OO2- 2- gain of 2e-)gain of 2e-)

IonsIonsThe loss or gain of e- to form ions is directly related to the number of The loss or gain of e- to form ions is directly related to the number of

valence e- in an atom All atoms have a driving force towards a noble valence e- in an atom All atoms have a driving force towards a noble gas e- configuration as this is the most stable configuration (ie 8 e- gas e- configuration as this is the most stable configuration (ie 8 e- in the valence shell unless we are talking about the 1in the valence shell unless we are talking about the 1stst shell which shell which only holds 2 e- as in He)only holds 2 e- as in He)

We can predict the ions that are formed by atoms by using the Periodic We can predict the ions that are formed by atoms by using the Periodic Table Table The group number (column number) indicates the The group number (column number) indicates the number of e- in the valence shellnumber of e- in the valence shell Therefore Therefore

Group I has one valence e- and will tend to lose 1e- forming a +1 ion and Group I has one valence e- and will tend to lose 1e- forming a +1 ion and Group VII has 7 valence e- and will tend to gain 1e- forming a -1 ion etcGroup VII has 7 valence e- and will tend to gain 1e- forming a -1 ion etc

The transition metals are more difficult to predict as many of these The transition metals are more difficult to predict as many of these elements have a variable e- configuration however these will all lose elements have a variable e- configuration however these will all lose electrons to form positive ionselectrons to form positive ions

In generalIn generalMetals tend to form cations (+) and non-metals tend to form Metals tend to form cations (+) and non-metals tend to form

anions (-)anions (-)

Ionic bondingIonic bondingIonic bonds are formed from the Ionic bonds are formed from the

transfer of electrons from one transfer of electrons from one atom to another As previously atom to another As previously stated this is to obtain an stated this is to obtain an overall noble gas overall noble gas configuration The ratio of configuration The ratio of atoms results in an electrically atoms results in an electrically neutral compoundneutral compound

Because oppositely charged Because oppositely charged particles attract to form these particles attract to form these bonds bonds ionic bonds tend to ionic bonds tend to form between metals and non-form between metals and non-metalsmetals

Note ionic compounds do not Note ionic compounds do not form discreet molecules form discreet molecules rather they tend to form an rather they tend to form an array of anions and cations in array of anions and cations in a fixed ratio which is given in a fixed ratio which is given in the the empirical formula (See empirical formula (See next slide)next slide)

Electrostatic attraction Electrostatic attraction between oppositely between oppositely charged particlescharged particles

+ -cation anion

ExampleExample

MgMg2+2+ + Cl + Cl-- MgCl MgCl22

Ionic bondingIonic bonding

No discreet molecules are formed in ionic No discreet molecules are formed in ionic bonding due to electrostatic forces bonding due to electrostatic forces holding the atoms together More holding the atoms together More information about these and their information about these and their properties in 825properties in 825-- --

-- -- --

--

-- --

---- --++

++

++

++++

++

++

++++++

Covalent BondingCovalent BondingCovalent bonds are formed between two atoms sharing electrons Covalent bonds are formed between two atoms sharing electrons

In covalent bonding there is no electrostatic attraction as in In covalent bonding there is no electrostatic attraction as in ionic bonding Atoms will lsquosharersquo a pair (single bond) or pairs ionic bonding Atoms will lsquosharersquo a pair (single bond) or pairs (double or triple bonds) of e- to gain a noble gas configuration (double or triple bonds) of e- to gain a noble gas configuration For exampleFor example

Cl with and electron configuration of (287) will covalently bond Cl with and electron configuration of (287) will covalently bond with another Cl of (287) or with H of (1) to form Clwith another Cl of (287) or with H of (1) to form Cl22 or HCl or HCl

In the examples of ClIn the examples of Cl22 and HCl all atoms have a full valence and HCl all atoms have a full valence shell due to the sharing of electrons Cl has 8 e- and H has 2 e- shell due to the sharing of electrons Cl has 8 e- and H has 2 e- These compounds then exist as individual particles or molecules These compounds then exist as individual particles or molecules and are known as and are known as covalent molecular substancescovalent molecular substances to distinguish to distinguish them from them from covalent latticescovalent lattices such as in silicon dioxide and such as in silicon dioxide and diamonddiamond

Other examples include water ammonia and carbon dioxideOther examples include water ammonia and carbon dioxide

Covalent BondingCovalent Bonding

Covalent bonding leads to the formation of Covalent bonding leads to the formation of discreet molecules (ie single units that discreet molecules (ie single units that are often weakly bonded together by are often weakly bonded together by intermolecular forcesintermolecular forces) More about these ) More about these and their properties in 825and their properties in 825

WaterWater ChloriChlorinene

HydrogeHydrogen n ChloriChloridede

Lewis Dot StructuresLewis Dot StructuresLewis dot structures are a Lewis dot structures are a

way of representing the way of representing the valence e- configuration valence e- configuration of an atom and show of an atom and show how valence e- are how valence e- are arranged in compoundsarranged in compounds

Lewis dot structures can Lewis dot structures can be used to show the be used to show the formation of ions but are formation of ions but are more commonly used to more commonly used to show covalent bondingshow covalent bonding

The compounds formed to The compounds formed to the right are methane the right are methane ammonia water and ammonia water and hydrogen chloride hydrogen chloride (hydrochloric acid)(hydrochloric acid)

82 The Chemical Earth82 The Chemical Earth

Focus 4Focus 4

Energy is required to extract Energy is required to extract elements from their naturally elements from their naturally

occurring sourcesoccurring sources

Physical vs ChemicalPhysical vs Chemical Physical ndash changes that are associated with Physical ndash changes that are associated with

physical properties which do not change physical properties which do not change the chemical composition of a substancethe chemical composition of a substance Eg hardness density malleability ductility Eg hardness density malleability ductility

electrical and thermal conductivities melting electrical and thermal conductivities melting point boiling point solubilitypoint boiling point solubility

Chemical ndash changes that occur when a Chemical ndash changes that occur when a substance breaks down or reacts with substance breaks down or reacts with another substance in a chemical reactionanother substance in a chemical reaction A new substance is always formed and has A new substance is always formed and has

different properties than the original reactantsdifferent properties than the original reactants

Physical Changes - Physical Changes - examplesexamples

Changing of state (melting iron boiling water)Changing of state (melting iron boiling water) Changing the physical appearance (crushing Changing the physical appearance (crushing

ore in a ball mill drawing copper into wires)ore in a ball mill drawing copper into wires) Dissolving a solid in a liquid (sugar into Dissolving a solid in a liquid (sugar into

water)water) Separation of mixtures (filtering sand from Separation of mixtures (filtering sand from

water separating sea salt from water)water separating sea salt from water)

Physical changes ndash no new substancesPhysical changes ndash no new substances

Chemical Changes - Chemical Changes - indicationsindications

A gas is evolved (iron and HCl generate HA gas is evolved (iron and HCl generate H22 gas) gas) A solid (precipitate) is formed when two A solid (precipitate) is formed when two

solutions are added together (silver nitrate and solutions are added together (silver nitrate and sodium chloride solutions produce a white solid sodium chloride solutions produce a white solid of silver chloride)of silver chloride)

A change in colour (purple potassium A change in colour (purple potassium permanganate (permanganate (KMnO4KMnO4) is added to hydrogen ) is added to hydrogen peroxide the solution turns colourless)peroxide the solution turns colourless)

Change of temperature (magnesium is burned Change of temperature (magnesium is burned in air and becomes very hot)in air and becomes very hot)

Chemical change ndash at least one new Chemical change ndash at least one new substancesubstance

Physical vs Chemical -Physical vs Chemical -WaterWater

Water- a physical Water- a physical changechange

Boiling water is an example Boiling water is an example of relatively weak of relatively weak intermolecular forces intermolecular forces (Hydrogen bonds) (Hydrogen bonds) breakingbreaking

Energy required = 44 kJmolEnergy required = 44 kJmol

Water-a chemical Water-a chemical changechange

Electrolysis of water involves Electrolysis of water involves the breaking of very the breaking of very strong covalent bonds strong covalent bonds between H and O atomsbetween H and O atoms

Energy required = 286 Energy required = 286 kJmolkJmol

Physical vs Chemical -Physical vs Chemical -WaterWater

Boiling ndash breaking H Boiling ndash breaking H bondsbonds

Electrolysis ndash Electrolysis ndash breaking covalent breaking covalent bondsbonds

OOHH

HHHHHH

OOHH

HH

OOHH

HH

OOHH

HH

OOHH

HH

H bondH bond

OO

OO

OOHH

HH

++++

HHHH

Physical vs Chemical -Physical vs Chemical -summarysummary

Chemical changeChemical change

(reaction)(reaction)Physical changePhysical change

At least one new At least one new substance is formedsubstance is formed

No new substances No new substances are formedare formed

Difficult to reverse Difficult to reverse (eg unboiled egg)(eg unboiled egg)

Easily reversed (eg Easily reversed (eg melt ice and freeze it melt ice and freeze it again)again)

Generally requires a Generally requires a large amount of large amount of energyenergy

Generally relatively Generally relatively small quantities of small quantities of energyenergy

Decomposition ReactionsDecomposition Reactions Energy absorbed Energy absorbed

When a compound decomposes into When a compound decomposes into two or more other pure substances two or more other pure substances energy is normally absorbed in the energy is normally absorbed in the form of heat light or electricityform of heat light or electricity

+ AB + AB A + B A + BHeatHeat

LightLight

ElectricityElectricity

Decomposition Reactions-Decomposition Reactions-examplesexamples

HeatHeatSolid Solid copper nitratecopper nitrate decomposes to solid decomposes to solid copper copper

oxideoxide nitrogen dioxidenitrogen dioxide and and oxygenoxygen gases gases

ElectricityElectricityMolten Molten lead bromidelead bromide (400 (40000C) forms C) forms brominebromine gas at gas at

the +ve electrode and liquid the +ve electrode and liquid leadlead at the ndashve at the ndashve electrodeelectrode

LightLightSolid Solid silver chloridesilver chloride decomposes to decomposes to silversilver metal and metal and

chlorinechlorine gas (decomposition of silver compounds gas (decomposition of silver compounds is the basis of photography development)is the basis of photography development)

Synthesis ReactionsSynthesis ReactionsEnergy releasedEnergy released

A synthesis or combination reaction A synthesis or combination reaction involves the combination of two or involves the combination of two or more pure substances When a more pure substances When a compound is formed from its compound is formed from its elements it is known as a elements it is known as a direct direct combination reactioncombination reaction These These reactions normally release energy reactions normally release energy

A + B A + B AB + energy AB + energy

Synthesis reactions - Synthesis reactions - examplesexamples

MagnesiumMagnesium burns in air ( burns in air (oxygenoxygen) to produce ) to produce magnesium oxidemagnesium oxide (light and heat energy (light and heat energy released)released)

HydrogenHydrogen and and oxygenoxygen combine in an combine in an explosive reaction to produce explosive reaction to produce waterwater (much (much energy released)energy released)

CopperCopper metal combines with yellow metal combines with yellow sulphursulphur when heated to produce when heated to produce copper (I) copper (I) sulphidesulphide (much heat energy is released) (much heat energy is released)

Decomposition and Decomposition and SynthesisSynthesis

Everyday ApplicationsEveryday ApplicationsDecompositionDecomposition

Air bags ndash sodium azide Air bags ndash sodium azide (NaN(NaN33) decomposes to ) decomposes to sodium and nitrogen gas by sodium and nitrogen gas by ignition with a detonating ignition with a detonating capcap

Limestone (primarily CaCOLimestone (primarily CaCO33) ) ndash decomposes to calcium ndash decomposes to calcium oxide and carbon dioxide by oxide and carbon dioxide by heating to make lime (CaO) heating to make lime (CaO) cement and glasscement and glass

Aluminium - the industrial Aluminium - the industrial process of electrolysing process of electrolysing aluminium oxide produces aluminium oxide produces aluminium metalaluminium metal

SynthesisSynthesis Rust ndash iron and oxygen Rust ndash iron and oxygen

combine in the presence of combine in the presence of water to form iron (III) oxidewater to form iron (III) oxide

Burning coke (primarily Burning coke (primarily carbon) is used as a fuel in carbon) is used as a fuel in smelting iron ore in a blast smelting iron ore in a blast furnace during the steel furnace during the steel making process making process

Pollutants - NO (nitric oxide Pollutants - NO (nitric oxide or nitrogen monoxide) and or nitrogen monoxide) and NO2 (nitrogen dioxide) are NO2 (nitrogen dioxide) are formed inside the formed inside the combustion chambers of cars combustion chambers of cars from nitrogen and oxygen from nitrogen and oxygen gasesgases

82 The Chemical Earth82 The Chemical Earth

Focus 5Focus 5

The properties of elements and The properties of elements and compounds are determined by compounds are determined by

their bonding and structuretheir bonding and structure

Properties of elements and Properties of elements and their compounds are very their compounds are very

differentdifferent8Fe(s) + S8Fe(s) + S88(s) + heat (s) + heat 8FeS(s) 8FeS(s)

substancsubstancee

colourcolour Melting Melting point point ((00C)C)

Boiling Boiling point point ((00C)C)

Density Density (gcm(gcm33))

magneticmagnetic

IronIron GreyGrey 15351535 27502750 7979 yesyes

SulphurSulphur YellowYellow 113113 445445 2121 nono

Iron (II) Iron (II) sulphidesulphide

Yellow-Yellow-goldgold

11941194 -- 484484 nono

Properties of elements Properties of elements compounds and mixtures compounds and mixtures

are very differentare very differentAluminiumAluminiumPhysical propertiesPhysical properties MP = 660MP = 66000CC Density = 27 gcmDensity = 27 gcm3 3

Conductivity = 378 x10Conductivity = 378 x1066 Smiddotm-1 Smiddotm-1 (20 degC)(20 degC)

Chemical propertiesChemical properties 4Al(s)+ 3O4Al(s)+ 3O22(g) (g) 2Al 2Al22OO33(s)(s) 2Al(s) + 6HCl(g) 2Al(s) + 6HCl(g) 2AlCl 2AlCl33(aq) (aq)

+ 3H+ 3H22(g)(g)

OxygenOxygenPhysical propertiesPhysical properties MP = -219MP = -21900CC Density = 00013 gcmDensity = 00013 gcm33

Conductivity = non-conductorConductivity = non-conductor

Bauxite ore Bauxite ore (Al(Al22OO33xHxH22O)O)Physical propertiesPhysical properties MP = 2045MP = 204500CC Density = 35-4 gcmDensity = 35-4 gcm33

Conductivity = non-conductorConductivity = non-conductor

Chemical propertiesChemical properties AlAl22OO33(s) + 2NaOH + 3H(s) + 2NaOH + 3H22O(l) O(l)

2Na[Al(OH)2Na[Al(OH)44](aq) (Bayer process)](aq) (Bayer process)

NB Bauxite is essentially an impure NB Bauxite is essentially an impure aluminium oxide The major aluminium oxide The major impurities include iron oxides impurities include iron oxides silicon dioxide and titanium silicon dioxide and titanium dioxide The impurities remain as dioxide The impurities remain as solids and do not react with solids and do not react with NaOH This process removes NaOH This process removes these impuritiesthese impurities

Structure of metalsStructure of metals

Metals can be described as three-Metals can be described as three-dimensional lattices of positive ions in a dimensional lattices of positive ions in a sea of delocalised electrons sea of delocalised electrons

Covalent BondingCovalent Bonding Covalent Molecular-strong Covalent Molecular-strong

bonds weak bonds weak intermolecular forces intermolecular forces holding molecules holding molecules togethertogether

Covalent Network-Covalent Network-covalent bonding lattice covalent bonding lattice that extends indefinitely that extends indefinitely throughout the crystalthroughout the crystal

Ionic bondingIonic bonding

No discreet molecules are formed in No discreet molecules are formed in ionic bonding due to electrostatic ionic bonding due to electrostatic forces holding the atoms together forces holding the atoms together They form a continuing 3D latticeThey form a continuing 3D lattice

-- --

-- -- --

--

-- --

---- --++

++

++

++++

++

++

++++++

Properties associated with Properties associated with bond typesbond types

Metallic bondingMetallic bonding High melting pointsHigh melting points-due to strong attraction between -due to strong attraction between

positively charged metal ions and delocalized positively charged metal ions and delocalized electrons The higher the valency the stronger the electrons The higher the valency the stronger the bond eg Cabond eg Ca2+2+ is stronger than K is stronger than K++

Good conductors of heat and electricityGood conductors of heat and electricity-due to the high -due to the high mobility of delocalized electrons Electrons enter and mobility of delocalized electrons Electrons enter and leave a metal easilyleave a metal easily

Malleable and ductileMalleable and ductile-due to delocalized electrons not -due to delocalized electrons not belonging to any particular metal atom Therefore one belonging to any particular metal atom Therefore one layer of ions can slide over another without disrupting layer of ions can slide over another without disrupting the bond between metal atoms The electrons and the bond between metal atoms The electrons and metal ions simply rearrangemetal ions simply rearrange

HardnessHardness- tend to be hard due to tightly packed atoms- tend to be hard due to tightly packed atoms

Properties associated with Properties associated with bond typesbond types

Ionic bondingIonic bonding High melting pointsHigh melting points-due to strong electrostatic attraction -due to strong electrostatic attraction

between anions and cationsbetween anions and cations

Non-conductors of electricity in solid stateNon-conductors of electricity in solid state-due to -due to oppositely charged particles which are in fixed positionsoppositely charged particles which are in fixed positions

Conductors in the liquid (molten) stateConductors in the liquid (molten) state-due to the ions -due to the ions being able to move freely through the liquidbeing able to move freely through the liquid

HardnessHardness-due to strong electrostatic attraction between -due to strong electrostatic attraction between oppositely charged particlesoppositely charged particles

BrittleBrittle-due to the fixed location of oppositely charged -due to the fixed location of oppositely charged particles Displacement of ions moves them closer to ions particles Displacement of ions moves them closer to ions of a similar charge which increases the repulsive forces of a similar charge which increases the repulsive forces along the fracturealong the fracture

Properties associated with Properties associated with bond typesbond types

Covalent molecular bondingCovalent molecular bonding Low melting pointsLow melting points-due to generally weak -due to generally weak

attractive forces between molecules There attractive forces between molecules There are exceptions to this rule (eg Iare exceptions to this rule (eg I22 melts at melts at 11411400C but decomposes at 1000C but decomposes at 100000C) C)

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

SoftSoft-due to weak forces existing between -due to weak forces existing between moleculesmolecules

Properties associated with Properties associated with bond typesbond types

Covalent Network bondingCovalent Network bonding Very high melting points and boiling Very high melting points and boiling

pointspoints-due to strong covalent bonding -due to strong covalent bonding which form rigid 3-D structureswhich form rigid 3-D structures

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

Extremely hardExtremely hard- due to strong covalent - due to strong covalent bonding which form rigid 3-D structuresbonding which form rigid 3-D structures

The Chemical EarthThe Chemical Earth

Compiled by Robert Slider (2006)

Please share this resource with others

IonsIonsThe loss or gain of e- to form ions is directly related to the number of The loss or gain of e- to form ions is directly related to the number of

valence e- in an atom All atoms have a driving force towards a noble valence e- in an atom All atoms have a driving force towards a noble gas e- configuration as this is the most stable configuration (ie 8 e- gas e- configuration as this is the most stable configuration (ie 8 e- in the valence shell unless we are talking about the 1in the valence shell unless we are talking about the 1stst shell which shell which only holds 2 e- as in He)only holds 2 e- as in He)

We can predict the ions that are formed by atoms by using the Periodic We can predict the ions that are formed by atoms by using the Periodic Table Table The group number (column number) indicates the The group number (column number) indicates the number of e- in the valence shellnumber of e- in the valence shell Therefore Therefore

Group I has one valence e- and will tend to lose 1e- forming a +1 ion and Group I has one valence e- and will tend to lose 1e- forming a +1 ion and Group VII has 7 valence e- and will tend to gain 1e- forming a -1 ion etcGroup VII has 7 valence e- and will tend to gain 1e- forming a -1 ion etc

The transition metals are more difficult to predict as many of these The transition metals are more difficult to predict as many of these elements have a variable e- configuration however these will all lose elements have a variable e- configuration however these will all lose electrons to form positive ionselectrons to form positive ions

In generalIn generalMetals tend to form cations (+) and non-metals tend to form Metals tend to form cations (+) and non-metals tend to form

anions (-)anions (-)

Ionic bondingIonic bondingIonic bonds are formed from the Ionic bonds are formed from the

transfer of electrons from one transfer of electrons from one atom to another As previously atom to another As previously stated this is to obtain an stated this is to obtain an overall noble gas overall noble gas configuration The ratio of configuration The ratio of atoms results in an electrically atoms results in an electrically neutral compoundneutral compound

Because oppositely charged Because oppositely charged particles attract to form these particles attract to form these bonds bonds ionic bonds tend to ionic bonds tend to form between metals and non-form between metals and non-metalsmetals

Note ionic compounds do not Note ionic compounds do not form discreet molecules form discreet molecules rather they tend to form an rather they tend to form an array of anions and cations in array of anions and cations in a fixed ratio which is given in a fixed ratio which is given in the the empirical formula (See empirical formula (See next slide)next slide)

Electrostatic attraction Electrostatic attraction between oppositely between oppositely charged particlescharged particles

+ -cation anion

ExampleExample

MgMg2+2+ + Cl + Cl-- MgCl MgCl22

Ionic bondingIonic bonding

No discreet molecules are formed in ionic No discreet molecules are formed in ionic bonding due to electrostatic forces bonding due to electrostatic forces holding the atoms together More holding the atoms together More information about these and their information about these and their properties in 825properties in 825-- --

-- -- --

--

-- --

---- --++

++

++

++++

++

++

++++++

Covalent BondingCovalent BondingCovalent bonds are formed between two atoms sharing electrons Covalent bonds are formed between two atoms sharing electrons

In covalent bonding there is no electrostatic attraction as in In covalent bonding there is no electrostatic attraction as in ionic bonding Atoms will lsquosharersquo a pair (single bond) or pairs ionic bonding Atoms will lsquosharersquo a pair (single bond) or pairs (double or triple bonds) of e- to gain a noble gas configuration (double or triple bonds) of e- to gain a noble gas configuration For exampleFor example

Cl with and electron configuration of (287) will covalently bond Cl with and electron configuration of (287) will covalently bond with another Cl of (287) or with H of (1) to form Clwith another Cl of (287) or with H of (1) to form Cl22 or HCl or HCl

In the examples of ClIn the examples of Cl22 and HCl all atoms have a full valence and HCl all atoms have a full valence shell due to the sharing of electrons Cl has 8 e- and H has 2 e- shell due to the sharing of electrons Cl has 8 e- and H has 2 e- These compounds then exist as individual particles or molecules These compounds then exist as individual particles or molecules and are known as and are known as covalent molecular substancescovalent molecular substances to distinguish to distinguish them from them from covalent latticescovalent lattices such as in silicon dioxide and such as in silicon dioxide and diamonddiamond

Other examples include water ammonia and carbon dioxideOther examples include water ammonia and carbon dioxide

Covalent BondingCovalent Bonding

Covalent bonding leads to the formation of Covalent bonding leads to the formation of discreet molecules (ie single units that discreet molecules (ie single units that are often weakly bonded together by are often weakly bonded together by intermolecular forcesintermolecular forces) More about these ) More about these and their properties in 825and their properties in 825

WaterWater ChloriChlorinene

HydrogeHydrogen n ChloriChloridede

Lewis Dot StructuresLewis Dot StructuresLewis dot structures are a Lewis dot structures are a

way of representing the way of representing the valence e- configuration valence e- configuration of an atom and show of an atom and show how valence e- are how valence e- are arranged in compoundsarranged in compounds

Lewis dot structures can Lewis dot structures can be used to show the be used to show the formation of ions but are formation of ions but are more commonly used to more commonly used to show covalent bondingshow covalent bonding

The compounds formed to The compounds formed to the right are methane the right are methane ammonia water and ammonia water and hydrogen chloride hydrogen chloride (hydrochloric acid)(hydrochloric acid)

82 The Chemical Earth82 The Chemical Earth

Focus 4Focus 4

Energy is required to extract Energy is required to extract elements from their naturally elements from their naturally

occurring sourcesoccurring sources

Physical vs ChemicalPhysical vs Chemical Physical ndash changes that are associated with Physical ndash changes that are associated with

physical properties which do not change physical properties which do not change the chemical composition of a substancethe chemical composition of a substance Eg hardness density malleability ductility Eg hardness density malleability ductility

electrical and thermal conductivities melting electrical and thermal conductivities melting point boiling point solubilitypoint boiling point solubility

Chemical ndash changes that occur when a Chemical ndash changes that occur when a substance breaks down or reacts with substance breaks down or reacts with another substance in a chemical reactionanother substance in a chemical reaction A new substance is always formed and has A new substance is always formed and has

different properties than the original reactantsdifferent properties than the original reactants

Physical Changes - Physical Changes - examplesexamples

Changing of state (melting iron boiling water)Changing of state (melting iron boiling water) Changing the physical appearance (crushing Changing the physical appearance (crushing

ore in a ball mill drawing copper into wires)ore in a ball mill drawing copper into wires) Dissolving a solid in a liquid (sugar into Dissolving a solid in a liquid (sugar into

water)water) Separation of mixtures (filtering sand from Separation of mixtures (filtering sand from

water separating sea salt from water)water separating sea salt from water)

Physical changes ndash no new substancesPhysical changes ndash no new substances

Chemical Changes - Chemical Changes - indicationsindications

A gas is evolved (iron and HCl generate HA gas is evolved (iron and HCl generate H22 gas) gas) A solid (precipitate) is formed when two A solid (precipitate) is formed when two

solutions are added together (silver nitrate and solutions are added together (silver nitrate and sodium chloride solutions produce a white solid sodium chloride solutions produce a white solid of silver chloride)of silver chloride)

A change in colour (purple potassium A change in colour (purple potassium permanganate (permanganate (KMnO4KMnO4) is added to hydrogen ) is added to hydrogen peroxide the solution turns colourless)peroxide the solution turns colourless)

Change of temperature (magnesium is burned Change of temperature (magnesium is burned in air and becomes very hot)in air and becomes very hot)

Chemical change ndash at least one new Chemical change ndash at least one new substancesubstance

Physical vs Chemical -Physical vs Chemical -WaterWater

Water- a physical Water- a physical changechange

Boiling water is an example Boiling water is an example of relatively weak of relatively weak intermolecular forces intermolecular forces (Hydrogen bonds) (Hydrogen bonds) breakingbreaking

Energy required = 44 kJmolEnergy required = 44 kJmol

Water-a chemical Water-a chemical changechange

Electrolysis of water involves Electrolysis of water involves the breaking of very the breaking of very strong covalent bonds strong covalent bonds between H and O atomsbetween H and O atoms

Energy required = 286 Energy required = 286 kJmolkJmol

Physical vs Chemical -Physical vs Chemical -WaterWater

Boiling ndash breaking H Boiling ndash breaking H bondsbonds

Electrolysis ndash Electrolysis ndash breaking covalent breaking covalent bondsbonds

OOHH

HHHHHH

OOHH

HH

OOHH

HH

OOHH

HH

OOHH

HH

H bondH bond

OO

OO

OOHH

HH

++++

HHHH

Physical vs Chemical -Physical vs Chemical -summarysummary

Chemical changeChemical change

(reaction)(reaction)Physical changePhysical change

At least one new At least one new substance is formedsubstance is formed

No new substances No new substances are formedare formed

Difficult to reverse Difficult to reverse (eg unboiled egg)(eg unboiled egg)

Easily reversed (eg Easily reversed (eg melt ice and freeze it melt ice and freeze it again)again)

Generally requires a Generally requires a large amount of large amount of energyenergy

Generally relatively Generally relatively small quantities of small quantities of energyenergy

Decomposition ReactionsDecomposition Reactions Energy absorbed Energy absorbed

When a compound decomposes into When a compound decomposes into two or more other pure substances two or more other pure substances energy is normally absorbed in the energy is normally absorbed in the form of heat light or electricityform of heat light or electricity

+ AB + AB A + B A + BHeatHeat

LightLight

ElectricityElectricity

Decomposition Reactions-Decomposition Reactions-examplesexamples

HeatHeatSolid Solid copper nitratecopper nitrate decomposes to solid decomposes to solid copper copper

oxideoxide nitrogen dioxidenitrogen dioxide and and oxygenoxygen gases gases

ElectricityElectricityMolten Molten lead bromidelead bromide (400 (40000C) forms C) forms brominebromine gas at gas at

the +ve electrode and liquid the +ve electrode and liquid leadlead at the ndashve at the ndashve electrodeelectrode

LightLightSolid Solid silver chloridesilver chloride decomposes to decomposes to silversilver metal and metal and

chlorinechlorine gas (decomposition of silver compounds gas (decomposition of silver compounds is the basis of photography development)is the basis of photography development)

Synthesis ReactionsSynthesis ReactionsEnergy releasedEnergy released

A synthesis or combination reaction A synthesis or combination reaction involves the combination of two or involves the combination of two or more pure substances When a more pure substances When a compound is formed from its compound is formed from its elements it is known as a elements it is known as a direct direct combination reactioncombination reaction These These reactions normally release energy reactions normally release energy

A + B A + B AB + energy AB + energy

Synthesis reactions - Synthesis reactions - examplesexamples

MagnesiumMagnesium burns in air ( burns in air (oxygenoxygen) to produce ) to produce magnesium oxidemagnesium oxide (light and heat energy (light and heat energy released)released)

HydrogenHydrogen and and oxygenoxygen combine in an combine in an explosive reaction to produce explosive reaction to produce waterwater (much (much energy released)energy released)

CopperCopper metal combines with yellow metal combines with yellow sulphursulphur when heated to produce when heated to produce copper (I) copper (I) sulphidesulphide (much heat energy is released) (much heat energy is released)

Decomposition and Decomposition and SynthesisSynthesis

Everyday ApplicationsEveryday ApplicationsDecompositionDecomposition

Air bags ndash sodium azide Air bags ndash sodium azide (NaN(NaN33) decomposes to ) decomposes to sodium and nitrogen gas by sodium and nitrogen gas by ignition with a detonating ignition with a detonating capcap

Limestone (primarily CaCOLimestone (primarily CaCO33) ) ndash decomposes to calcium ndash decomposes to calcium oxide and carbon dioxide by oxide and carbon dioxide by heating to make lime (CaO) heating to make lime (CaO) cement and glasscement and glass

Aluminium - the industrial Aluminium - the industrial process of electrolysing process of electrolysing aluminium oxide produces aluminium oxide produces aluminium metalaluminium metal

SynthesisSynthesis Rust ndash iron and oxygen Rust ndash iron and oxygen

combine in the presence of combine in the presence of water to form iron (III) oxidewater to form iron (III) oxide

Burning coke (primarily Burning coke (primarily carbon) is used as a fuel in carbon) is used as a fuel in smelting iron ore in a blast smelting iron ore in a blast furnace during the steel furnace during the steel making process making process

Pollutants - NO (nitric oxide Pollutants - NO (nitric oxide or nitrogen monoxide) and or nitrogen monoxide) and NO2 (nitrogen dioxide) are NO2 (nitrogen dioxide) are formed inside the formed inside the combustion chambers of cars combustion chambers of cars from nitrogen and oxygen from nitrogen and oxygen gasesgases

82 The Chemical Earth82 The Chemical Earth

Focus 5Focus 5

The properties of elements and The properties of elements and compounds are determined by compounds are determined by

their bonding and structuretheir bonding and structure

Properties of elements and Properties of elements and their compounds are very their compounds are very

differentdifferent8Fe(s) + S8Fe(s) + S88(s) + heat (s) + heat 8FeS(s) 8FeS(s)

substancsubstancee

colourcolour Melting Melting point point ((00C)C)

Boiling Boiling point point ((00C)C)

Density Density (gcm(gcm33))

magneticmagnetic

IronIron GreyGrey 15351535 27502750 7979 yesyes

SulphurSulphur YellowYellow 113113 445445 2121 nono

Iron (II) Iron (II) sulphidesulphide

Yellow-Yellow-goldgold

11941194 -- 484484 nono

Properties of elements Properties of elements compounds and mixtures compounds and mixtures

are very differentare very differentAluminiumAluminiumPhysical propertiesPhysical properties MP = 660MP = 66000CC Density = 27 gcmDensity = 27 gcm3 3

Conductivity = 378 x10Conductivity = 378 x1066 Smiddotm-1 Smiddotm-1 (20 degC)(20 degC)

Chemical propertiesChemical properties 4Al(s)+ 3O4Al(s)+ 3O22(g) (g) 2Al 2Al22OO33(s)(s) 2Al(s) + 6HCl(g) 2Al(s) + 6HCl(g) 2AlCl 2AlCl33(aq) (aq)

+ 3H+ 3H22(g)(g)

OxygenOxygenPhysical propertiesPhysical properties MP = -219MP = -21900CC Density = 00013 gcmDensity = 00013 gcm33

Conductivity = non-conductorConductivity = non-conductor

Bauxite ore Bauxite ore (Al(Al22OO33xHxH22O)O)Physical propertiesPhysical properties MP = 2045MP = 204500CC Density = 35-4 gcmDensity = 35-4 gcm33

Conductivity = non-conductorConductivity = non-conductor

Chemical propertiesChemical properties AlAl22OO33(s) + 2NaOH + 3H(s) + 2NaOH + 3H22O(l) O(l)

2Na[Al(OH)2Na[Al(OH)44](aq) (Bayer process)](aq) (Bayer process)

NB Bauxite is essentially an impure NB Bauxite is essentially an impure aluminium oxide The major aluminium oxide The major impurities include iron oxides impurities include iron oxides silicon dioxide and titanium silicon dioxide and titanium dioxide The impurities remain as dioxide The impurities remain as solids and do not react with solids and do not react with NaOH This process removes NaOH This process removes these impuritiesthese impurities

Structure of metalsStructure of metals

Metals can be described as three-Metals can be described as three-dimensional lattices of positive ions in a dimensional lattices of positive ions in a sea of delocalised electrons sea of delocalised electrons

Covalent BondingCovalent Bonding Covalent Molecular-strong Covalent Molecular-strong

bonds weak bonds weak intermolecular forces intermolecular forces holding molecules holding molecules togethertogether

Covalent Network-Covalent Network-covalent bonding lattice covalent bonding lattice that extends indefinitely that extends indefinitely throughout the crystalthroughout the crystal

Ionic bondingIonic bonding

No discreet molecules are formed in No discreet molecules are formed in ionic bonding due to electrostatic ionic bonding due to electrostatic forces holding the atoms together forces holding the atoms together They form a continuing 3D latticeThey form a continuing 3D lattice

-- --

-- -- --

--

-- --

---- --++

++

++

++++

++

++

++++++

Properties associated with Properties associated with bond typesbond types

Metallic bondingMetallic bonding High melting pointsHigh melting points-due to strong attraction between -due to strong attraction between

positively charged metal ions and delocalized positively charged metal ions and delocalized electrons The higher the valency the stronger the electrons The higher the valency the stronger the bond eg Cabond eg Ca2+2+ is stronger than K is stronger than K++

Good conductors of heat and electricityGood conductors of heat and electricity-due to the high -due to the high mobility of delocalized electrons Electrons enter and mobility of delocalized electrons Electrons enter and leave a metal easilyleave a metal easily

Malleable and ductileMalleable and ductile-due to delocalized electrons not -due to delocalized electrons not belonging to any particular metal atom Therefore one belonging to any particular metal atom Therefore one layer of ions can slide over another without disrupting layer of ions can slide over another without disrupting the bond between metal atoms The electrons and the bond between metal atoms The electrons and metal ions simply rearrangemetal ions simply rearrange

HardnessHardness- tend to be hard due to tightly packed atoms- tend to be hard due to tightly packed atoms

Properties associated with Properties associated with bond typesbond types

Ionic bondingIonic bonding High melting pointsHigh melting points-due to strong electrostatic attraction -due to strong electrostatic attraction

between anions and cationsbetween anions and cations

Non-conductors of electricity in solid stateNon-conductors of electricity in solid state-due to -due to oppositely charged particles which are in fixed positionsoppositely charged particles which are in fixed positions

Conductors in the liquid (molten) stateConductors in the liquid (molten) state-due to the ions -due to the ions being able to move freely through the liquidbeing able to move freely through the liquid

HardnessHardness-due to strong electrostatic attraction between -due to strong electrostatic attraction between oppositely charged particlesoppositely charged particles

BrittleBrittle-due to the fixed location of oppositely charged -due to the fixed location of oppositely charged particles Displacement of ions moves them closer to ions particles Displacement of ions moves them closer to ions of a similar charge which increases the repulsive forces of a similar charge which increases the repulsive forces along the fracturealong the fracture

Properties associated with Properties associated with bond typesbond types

Covalent molecular bondingCovalent molecular bonding Low melting pointsLow melting points-due to generally weak -due to generally weak

attractive forces between molecules There attractive forces between molecules There are exceptions to this rule (eg Iare exceptions to this rule (eg I22 melts at melts at 11411400C but decomposes at 1000C but decomposes at 100000C) C)

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

SoftSoft-due to weak forces existing between -due to weak forces existing between moleculesmolecules

Properties associated with Properties associated with bond typesbond types

Covalent Network bondingCovalent Network bonding Very high melting points and boiling Very high melting points and boiling

pointspoints-due to strong covalent bonding -due to strong covalent bonding which form rigid 3-D structureswhich form rigid 3-D structures

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

Extremely hardExtremely hard- due to strong covalent - due to strong covalent bonding which form rigid 3-D structuresbonding which form rigid 3-D structures

The Chemical EarthThe Chemical Earth

Compiled by Robert Slider (2006)

Please share this resource with others

Ionic bondingIonic bondingIonic bonds are formed from the Ionic bonds are formed from the

transfer of electrons from one transfer of electrons from one atom to another As previously atom to another As previously stated this is to obtain an stated this is to obtain an overall noble gas overall noble gas configuration The ratio of configuration The ratio of atoms results in an electrically atoms results in an electrically neutral compoundneutral compound

Because oppositely charged Because oppositely charged particles attract to form these particles attract to form these bonds bonds ionic bonds tend to ionic bonds tend to form between metals and non-form between metals and non-metalsmetals

Note ionic compounds do not Note ionic compounds do not form discreet molecules form discreet molecules rather they tend to form an rather they tend to form an array of anions and cations in array of anions and cations in a fixed ratio which is given in a fixed ratio which is given in the the empirical formula (See empirical formula (See next slide)next slide)

Electrostatic attraction Electrostatic attraction between oppositely between oppositely charged particlescharged particles

+ -cation anion

ExampleExample

MgMg2+2+ + Cl + Cl-- MgCl MgCl22

Ionic bondingIonic bonding

No discreet molecules are formed in ionic No discreet molecules are formed in ionic bonding due to electrostatic forces bonding due to electrostatic forces holding the atoms together More holding the atoms together More information about these and their information about these and their properties in 825properties in 825-- --

-- -- --

--

-- --

---- --++

++

++

++++

++

++

++++++

Covalent BondingCovalent BondingCovalent bonds are formed between two atoms sharing electrons Covalent bonds are formed between two atoms sharing electrons

In covalent bonding there is no electrostatic attraction as in In covalent bonding there is no electrostatic attraction as in ionic bonding Atoms will lsquosharersquo a pair (single bond) or pairs ionic bonding Atoms will lsquosharersquo a pair (single bond) or pairs (double or triple bonds) of e- to gain a noble gas configuration (double or triple bonds) of e- to gain a noble gas configuration For exampleFor example

Cl with and electron configuration of (287) will covalently bond Cl with and electron configuration of (287) will covalently bond with another Cl of (287) or with H of (1) to form Clwith another Cl of (287) or with H of (1) to form Cl22 or HCl or HCl

In the examples of ClIn the examples of Cl22 and HCl all atoms have a full valence and HCl all atoms have a full valence shell due to the sharing of electrons Cl has 8 e- and H has 2 e- shell due to the sharing of electrons Cl has 8 e- and H has 2 e- These compounds then exist as individual particles or molecules These compounds then exist as individual particles or molecules and are known as and are known as covalent molecular substancescovalent molecular substances to distinguish to distinguish them from them from covalent latticescovalent lattices such as in silicon dioxide and such as in silicon dioxide and diamonddiamond

Other examples include water ammonia and carbon dioxideOther examples include water ammonia and carbon dioxide

Covalent BondingCovalent Bonding

Covalent bonding leads to the formation of Covalent bonding leads to the formation of discreet molecules (ie single units that discreet molecules (ie single units that are often weakly bonded together by are often weakly bonded together by intermolecular forcesintermolecular forces) More about these ) More about these and their properties in 825and their properties in 825

WaterWater ChloriChlorinene

HydrogeHydrogen n ChloriChloridede

Lewis Dot StructuresLewis Dot StructuresLewis dot structures are a Lewis dot structures are a

way of representing the way of representing the valence e- configuration valence e- configuration of an atom and show of an atom and show how valence e- are how valence e- are arranged in compoundsarranged in compounds

Lewis dot structures can Lewis dot structures can be used to show the be used to show the formation of ions but are formation of ions but are more commonly used to more commonly used to show covalent bondingshow covalent bonding

The compounds formed to The compounds formed to the right are methane the right are methane ammonia water and ammonia water and hydrogen chloride hydrogen chloride (hydrochloric acid)(hydrochloric acid)

82 The Chemical Earth82 The Chemical Earth

Focus 4Focus 4

Energy is required to extract Energy is required to extract elements from their naturally elements from their naturally

occurring sourcesoccurring sources

Physical vs ChemicalPhysical vs Chemical Physical ndash changes that are associated with Physical ndash changes that are associated with

physical properties which do not change physical properties which do not change the chemical composition of a substancethe chemical composition of a substance Eg hardness density malleability ductility Eg hardness density malleability ductility

electrical and thermal conductivities melting electrical and thermal conductivities melting point boiling point solubilitypoint boiling point solubility

Chemical ndash changes that occur when a Chemical ndash changes that occur when a substance breaks down or reacts with substance breaks down or reacts with another substance in a chemical reactionanother substance in a chemical reaction A new substance is always formed and has A new substance is always formed and has

different properties than the original reactantsdifferent properties than the original reactants

Physical Changes - Physical Changes - examplesexamples

Changing of state (melting iron boiling water)Changing of state (melting iron boiling water) Changing the physical appearance (crushing Changing the physical appearance (crushing

ore in a ball mill drawing copper into wires)ore in a ball mill drawing copper into wires) Dissolving a solid in a liquid (sugar into Dissolving a solid in a liquid (sugar into

water)water) Separation of mixtures (filtering sand from Separation of mixtures (filtering sand from

water separating sea salt from water)water separating sea salt from water)

Physical changes ndash no new substancesPhysical changes ndash no new substances

Chemical Changes - Chemical Changes - indicationsindications

A gas is evolved (iron and HCl generate HA gas is evolved (iron and HCl generate H22 gas) gas) A solid (precipitate) is formed when two A solid (precipitate) is formed when two

solutions are added together (silver nitrate and solutions are added together (silver nitrate and sodium chloride solutions produce a white solid sodium chloride solutions produce a white solid of silver chloride)of silver chloride)

A change in colour (purple potassium A change in colour (purple potassium permanganate (permanganate (KMnO4KMnO4) is added to hydrogen ) is added to hydrogen peroxide the solution turns colourless)peroxide the solution turns colourless)

Change of temperature (magnesium is burned Change of temperature (magnesium is burned in air and becomes very hot)in air and becomes very hot)

Chemical change ndash at least one new Chemical change ndash at least one new substancesubstance

Physical vs Chemical -Physical vs Chemical -WaterWater

Water- a physical Water- a physical changechange

Boiling water is an example Boiling water is an example of relatively weak of relatively weak intermolecular forces intermolecular forces (Hydrogen bonds) (Hydrogen bonds) breakingbreaking

Energy required = 44 kJmolEnergy required = 44 kJmol

Water-a chemical Water-a chemical changechange

Electrolysis of water involves Electrolysis of water involves the breaking of very the breaking of very strong covalent bonds strong covalent bonds between H and O atomsbetween H and O atoms

Energy required = 286 Energy required = 286 kJmolkJmol

Physical vs Chemical -Physical vs Chemical -WaterWater

Boiling ndash breaking H Boiling ndash breaking H bondsbonds

Electrolysis ndash Electrolysis ndash breaking covalent breaking covalent bondsbonds

OOHH

HHHHHH

OOHH

HH

OOHH

HH

OOHH

HH

OOHH

HH

H bondH bond

OO

OO

OOHH

HH

++++

HHHH

Physical vs Chemical -Physical vs Chemical -summarysummary

Chemical changeChemical change

(reaction)(reaction)Physical changePhysical change

At least one new At least one new substance is formedsubstance is formed

No new substances No new substances are formedare formed

Difficult to reverse Difficult to reverse (eg unboiled egg)(eg unboiled egg)

Easily reversed (eg Easily reversed (eg melt ice and freeze it melt ice and freeze it again)again)

Generally requires a Generally requires a large amount of large amount of energyenergy

Generally relatively Generally relatively small quantities of small quantities of energyenergy

Decomposition ReactionsDecomposition Reactions Energy absorbed Energy absorbed

When a compound decomposes into When a compound decomposes into two or more other pure substances two or more other pure substances energy is normally absorbed in the energy is normally absorbed in the form of heat light or electricityform of heat light or electricity

+ AB + AB A + B A + BHeatHeat

LightLight

ElectricityElectricity

Decomposition Reactions-Decomposition Reactions-examplesexamples

HeatHeatSolid Solid copper nitratecopper nitrate decomposes to solid decomposes to solid copper copper

oxideoxide nitrogen dioxidenitrogen dioxide and and oxygenoxygen gases gases

ElectricityElectricityMolten Molten lead bromidelead bromide (400 (40000C) forms C) forms brominebromine gas at gas at

the +ve electrode and liquid the +ve electrode and liquid leadlead at the ndashve at the ndashve electrodeelectrode

LightLightSolid Solid silver chloridesilver chloride decomposes to decomposes to silversilver metal and metal and

chlorinechlorine gas (decomposition of silver compounds gas (decomposition of silver compounds is the basis of photography development)is the basis of photography development)

Synthesis ReactionsSynthesis ReactionsEnergy releasedEnergy released

A synthesis or combination reaction A synthesis or combination reaction involves the combination of two or involves the combination of two or more pure substances When a more pure substances When a compound is formed from its compound is formed from its elements it is known as a elements it is known as a direct direct combination reactioncombination reaction These These reactions normally release energy reactions normally release energy

A + B A + B AB + energy AB + energy

Synthesis reactions - Synthesis reactions - examplesexamples

MagnesiumMagnesium burns in air ( burns in air (oxygenoxygen) to produce ) to produce magnesium oxidemagnesium oxide (light and heat energy (light and heat energy released)released)

HydrogenHydrogen and and oxygenoxygen combine in an combine in an explosive reaction to produce explosive reaction to produce waterwater (much (much energy released)energy released)

CopperCopper metal combines with yellow metal combines with yellow sulphursulphur when heated to produce when heated to produce copper (I) copper (I) sulphidesulphide (much heat energy is released) (much heat energy is released)

Decomposition and Decomposition and SynthesisSynthesis

Everyday ApplicationsEveryday ApplicationsDecompositionDecomposition

Air bags ndash sodium azide Air bags ndash sodium azide (NaN(NaN33) decomposes to ) decomposes to sodium and nitrogen gas by sodium and nitrogen gas by ignition with a detonating ignition with a detonating capcap

Limestone (primarily CaCOLimestone (primarily CaCO33) ) ndash decomposes to calcium ndash decomposes to calcium oxide and carbon dioxide by oxide and carbon dioxide by heating to make lime (CaO) heating to make lime (CaO) cement and glasscement and glass

Aluminium - the industrial Aluminium - the industrial process of electrolysing process of electrolysing aluminium oxide produces aluminium oxide produces aluminium metalaluminium metal

SynthesisSynthesis Rust ndash iron and oxygen Rust ndash iron and oxygen

combine in the presence of combine in the presence of water to form iron (III) oxidewater to form iron (III) oxide

Burning coke (primarily Burning coke (primarily carbon) is used as a fuel in carbon) is used as a fuel in smelting iron ore in a blast smelting iron ore in a blast furnace during the steel furnace during the steel making process making process

Pollutants - NO (nitric oxide Pollutants - NO (nitric oxide or nitrogen monoxide) and or nitrogen monoxide) and NO2 (nitrogen dioxide) are NO2 (nitrogen dioxide) are formed inside the formed inside the combustion chambers of cars combustion chambers of cars from nitrogen and oxygen from nitrogen and oxygen gasesgases

82 The Chemical Earth82 The Chemical Earth

Focus 5Focus 5

The properties of elements and The properties of elements and compounds are determined by compounds are determined by

their bonding and structuretheir bonding and structure

Properties of elements and Properties of elements and their compounds are very their compounds are very

differentdifferent8Fe(s) + S8Fe(s) + S88(s) + heat (s) + heat 8FeS(s) 8FeS(s)

substancsubstancee

colourcolour Melting Melting point point ((00C)C)

Boiling Boiling point point ((00C)C)

Density Density (gcm(gcm33))

magneticmagnetic

IronIron GreyGrey 15351535 27502750 7979 yesyes

SulphurSulphur YellowYellow 113113 445445 2121 nono

Iron (II) Iron (II) sulphidesulphide

Yellow-Yellow-goldgold

11941194 -- 484484 nono

Properties of elements Properties of elements compounds and mixtures compounds and mixtures

are very differentare very differentAluminiumAluminiumPhysical propertiesPhysical properties MP = 660MP = 66000CC Density = 27 gcmDensity = 27 gcm3 3

Conductivity = 378 x10Conductivity = 378 x1066 Smiddotm-1 Smiddotm-1 (20 degC)(20 degC)

Chemical propertiesChemical properties 4Al(s)+ 3O4Al(s)+ 3O22(g) (g) 2Al 2Al22OO33(s)(s) 2Al(s) + 6HCl(g) 2Al(s) + 6HCl(g) 2AlCl 2AlCl33(aq) (aq)

+ 3H+ 3H22(g)(g)

OxygenOxygenPhysical propertiesPhysical properties MP = -219MP = -21900CC Density = 00013 gcmDensity = 00013 gcm33

Conductivity = non-conductorConductivity = non-conductor

Bauxite ore Bauxite ore (Al(Al22OO33xHxH22O)O)Physical propertiesPhysical properties MP = 2045MP = 204500CC Density = 35-4 gcmDensity = 35-4 gcm33

Conductivity = non-conductorConductivity = non-conductor

Chemical propertiesChemical properties AlAl22OO33(s) + 2NaOH + 3H(s) + 2NaOH + 3H22O(l) O(l)

2Na[Al(OH)2Na[Al(OH)44](aq) (Bayer process)](aq) (Bayer process)

NB Bauxite is essentially an impure NB Bauxite is essentially an impure aluminium oxide The major aluminium oxide The major impurities include iron oxides impurities include iron oxides silicon dioxide and titanium silicon dioxide and titanium dioxide The impurities remain as dioxide The impurities remain as solids and do not react with solids and do not react with NaOH This process removes NaOH This process removes these impuritiesthese impurities

Structure of metalsStructure of metals

Metals can be described as three-Metals can be described as three-dimensional lattices of positive ions in a dimensional lattices of positive ions in a sea of delocalised electrons sea of delocalised electrons

Covalent BondingCovalent Bonding Covalent Molecular-strong Covalent Molecular-strong

bonds weak bonds weak intermolecular forces intermolecular forces holding molecules holding molecules togethertogether

Covalent Network-Covalent Network-covalent bonding lattice covalent bonding lattice that extends indefinitely that extends indefinitely throughout the crystalthroughout the crystal

Ionic bondingIonic bonding

No discreet molecules are formed in No discreet molecules are formed in ionic bonding due to electrostatic ionic bonding due to electrostatic forces holding the atoms together forces holding the atoms together They form a continuing 3D latticeThey form a continuing 3D lattice

-- --

-- -- --

--

-- --

---- --++

++

++

++++

++

++

++++++

Properties associated with Properties associated with bond typesbond types

Metallic bondingMetallic bonding High melting pointsHigh melting points-due to strong attraction between -due to strong attraction between

positively charged metal ions and delocalized positively charged metal ions and delocalized electrons The higher the valency the stronger the electrons The higher the valency the stronger the bond eg Cabond eg Ca2+2+ is stronger than K is stronger than K++

Good conductors of heat and electricityGood conductors of heat and electricity-due to the high -due to the high mobility of delocalized electrons Electrons enter and mobility of delocalized electrons Electrons enter and leave a metal easilyleave a metal easily

Malleable and ductileMalleable and ductile-due to delocalized electrons not -due to delocalized electrons not belonging to any particular metal atom Therefore one belonging to any particular metal atom Therefore one layer of ions can slide over another without disrupting layer of ions can slide over another without disrupting the bond between metal atoms The electrons and the bond between metal atoms The electrons and metal ions simply rearrangemetal ions simply rearrange

HardnessHardness- tend to be hard due to tightly packed atoms- tend to be hard due to tightly packed atoms

Properties associated with Properties associated with bond typesbond types

Ionic bondingIonic bonding High melting pointsHigh melting points-due to strong electrostatic attraction -due to strong electrostatic attraction

between anions and cationsbetween anions and cations

Non-conductors of electricity in solid stateNon-conductors of electricity in solid state-due to -due to oppositely charged particles which are in fixed positionsoppositely charged particles which are in fixed positions

Conductors in the liquid (molten) stateConductors in the liquid (molten) state-due to the ions -due to the ions being able to move freely through the liquidbeing able to move freely through the liquid

HardnessHardness-due to strong electrostatic attraction between -due to strong electrostatic attraction between oppositely charged particlesoppositely charged particles

BrittleBrittle-due to the fixed location of oppositely charged -due to the fixed location of oppositely charged particles Displacement of ions moves them closer to ions particles Displacement of ions moves them closer to ions of a similar charge which increases the repulsive forces of a similar charge which increases the repulsive forces along the fracturealong the fracture

Properties associated with Properties associated with bond typesbond types

Covalent molecular bondingCovalent molecular bonding Low melting pointsLow melting points-due to generally weak -due to generally weak

attractive forces between molecules There attractive forces between molecules There are exceptions to this rule (eg Iare exceptions to this rule (eg I22 melts at melts at 11411400C but decomposes at 1000C but decomposes at 100000C) C)

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

SoftSoft-due to weak forces existing between -due to weak forces existing between moleculesmolecules

Properties associated with Properties associated with bond typesbond types

Covalent Network bondingCovalent Network bonding Very high melting points and boiling Very high melting points and boiling

pointspoints-due to strong covalent bonding -due to strong covalent bonding which form rigid 3-D structureswhich form rigid 3-D structures

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

Extremely hardExtremely hard- due to strong covalent - due to strong covalent bonding which form rigid 3-D structuresbonding which form rigid 3-D structures

The Chemical EarthThe Chemical Earth

Compiled by Robert Slider (2006)

Please share this resource with others

Ionic bondingIonic bonding

No discreet molecules are formed in ionic No discreet molecules are formed in ionic bonding due to electrostatic forces bonding due to electrostatic forces holding the atoms together More holding the atoms together More information about these and their information about these and their properties in 825properties in 825-- --

-- -- --

--

-- --

---- --++

++

++

++++

++

++

++++++

Covalent BondingCovalent BondingCovalent bonds are formed between two atoms sharing electrons Covalent bonds are formed between two atoms sharing electrons

In covalent bonding there is no electrostatic attraction as in In covalent bonding there is no electrostatic attraction as in ionic bonding Atoms will lsquosharersquo a pair (single bond) or pairs ionic bonding Atoms will lsquosharersquo a pair (single bond) or pairs (double or triple bonds) of e- to gain a noble gas configuration (double or triple bonds) of e- to gain a noble gas configuration For exampleFor example

Cl with and electron configuration of (287) will covalently bond Cl with and electron configuration of (287) will covalently bond with another Cl of (287) or with H of (1) to form Clwith another Cl of (287) or with H of (1) to form Cl22 or HCl or HCl

In the examples of ClIn the examples of Cl22 and HCl all atoms have a full valence and HCl all atoms have a full valence shell due to the sharing of electrons Cl has 8 e- and H has 2 e- shell due to the sharing of electrons Cl has 8 e- and H has 2 e- These compounds then exist as individual particles or molecules These compounds then exist as individual particles or molecules and are known as and are known as covalent molecular substancescovalent molecular substances to distinguish to distinguish them from them from covalent latticescovalent lattices such as in silicon dioxide and such as in silicon dioxide and diamonddiamond

Other examples include water ammonia and carbon dioxideOther examples include water ammonia and carbon dioxide

Covalent BondingCovalent Bonding

Covalent bonding leads to the formation of Covalent bonding leads to the formation of discreet molecules (ie single units that discreet molecules (ie single units that are often weakly bonded together by are often weakly bonded together by intermolecular forcesintermolecular forces) More about these ) More about these and their properties in 825and their properties in 825

WaterWater ChloriChlorinene

HydrogeHydrogen n ChloriChloridede

Lewis Dot StructuresLewis Dot StructuresLewis dot structures are a Lewis dot structures are a

way of representing the way of representing the valence e- configuration valence e- configuration of an atom and show of an atom and show how valence e- are how valence e- are arranged in compoundsarranged in compounds

Lewis dot structures can Lewis dot structures can be used to show the be used to show the formation of ions but are formation of ions but are more commonly used to more commonly used to show covalent bondingshow covalent bonding

The compounds formed to The compounds formed to the right are methane the right are methane ammonia water and ammonia water and hydrogen chloride hydrogen chloride (hydrochloric acid)(hydrochloric acid)

82 The Chemical Earth82 The Chemical Earth

Focus 4Focus 4

Energy is required to extract Energy is required to extract elements from their naturally elements from their naturally

occurring sourcesoccurring sources

Physical vs ChemicalPhysical vs Chemical Physical ndash changes that are associated with Physical ndash changes that are associated with

physical properties which do not change physical properties which do not change the chemical composition of a substancethe chemical composition of a substance Eg hardness density malleability ductility Eg hardness density malleability ductility

electrical and thermal conductivities melting electrical and thermal conductivities melting point boiling point solubilitypoint boiling point solubility

Chemical ndash changes that occur when a Chemical ndash changes that occur when a substance breaks down or reacts with substance breaks down or reacts with another substance in a chemical reactionanother substance in a chemical reaction A new substance is always formed and has A new substance is always formed and has

different properties than the original reactantsdifferent properties than the original reactants

Physical Changes - Physical Changes - examplesexamples

Changing of state (melting iron boiling water)Changing of state (melting iron boiling water) Changing the physical appearance (crushing Changing the physical appearance (crushing

ore in a ball mill drawing copper into wires)ore in a ball mill drawing copper into wires) Dissolving a solid in a liquid (sugar into Dissolving a solid in a liquid (sugar into

water)water) Separation of mixtures (filtering sand from Separation of mixtures (filtering sand from

water separating sea salt from water)water separating sea salt from water)

Physical changes ndash no new substancesPhysical changes ndash no new substances

Chemical Changes - Chemical Changes - indicationsindications

A gas is evolved (iron and HCl generate HA gas is evolved (iron and HCl generate H22 gas) gas) A solid (precipitate) is formed when two A solid (precipitate) is formed when two

solutions are added together (silver nitrate and solutions are added together (silver nitrate and sodium chloride solutions produce a white solid sodium chloride solutions produce a white solid of silver chloride)of silver chloride)

A change in colour (purple potassium A change in colour (purple potassium permanganate (permanganate (KMnO4KMnO4) is added to hydrogen ) is added to hydrogen peroxide the solution turns colourless)peroxide the solution turns colourless)

Change of temperature (magnesium is burned Change of temperature (magnesium is burned in air and becomes very hot)in air and becomes very hot)

Chemical change ndash at least one new Chemical change ndash at least one new substancesubstance

Physical vs Chemical -Physical vs Chemical -WaterWater

Water- a physical Water- a physical changechange

Boiling water is an example Boiling water is an example of relatively weak of relatively weak intermolecular forces intermolecular forces (Hydrogen bonds) (Hydrogen bonds) breakingbreaking

Energy required = 44 kJmolEnergy required = 44 kJmol

Water-a chemical Water-a chemical changechange

Electrolysis of water involves Electrolysis of water involves the breaking of very the breaking of very strong covalent bonds strong covalent bonds between H and O atomsbetween H and O atoms

Energy required = 286 Energy required = 286 kJmolkJmol

Physical vs Chemical -Physical vs Chemical -WaterWater

Boiling ndash breaking H Boiling ndash breaking H bondsbonds

Electrolysis ndash Electrolysis ndash breaking covalent breaking covalent bondsbonds

OOHH

HHHHHH

OOHH

HH

OOHH

HH

OOHH

HH

OOHH

HH

H bondH bond

OO

OO

OOHH

HH

++++

HHHH

Physical vs Chemical -Physical vs Chemical -summarysummary

Chemical changeChemical change

(reaction)(reaction)Physical changePhysical change

At least one new At least one new substance is formedsubstance is formed

No new substances No new substances are formedare formed

Difficult to reverse Difficult to reverse (eg unboiled egg)(eg unboiled egg)

Easily reversed (eg Easily reversed (eg melt ice and freeze it melt ice and freeze it again)again)

Generally requires a Generally requires a large amount of large amount of energyenergy

Generally relatively Generally relatively small quantities of small quantities of energyenergy

Decomposition ReactionsDecomposition Reactions Energy absorbed Energy absorbed

When a compound decomposes into When a compound decomposes into two or more other pure substances two or more other pure substances energy is normally absorbed in the energy is normally absorbed in the form of heat light or electricityform of heat light or electricity

+ AB + AB A + B A + BHeatHeat

LightLight

ElectricityElectricity

Decomposition Reactions-Decomposition Reactions-examplesexamples

HeatHeatSolid Solid copper nitratecopper nitrate decomposes to solid decomposes to solid copper copper

oxideoxide nitrogen dioxidenitrogen dioxide and and oxygenoxygen gases gases

ElectricityElectricityMolten Molten lead bromidelead bromide (400 (40000C) forms C) forms brominebromine gas at gas at

the +ve electrode and liquid the +ve electrode and liquid leadlead at the ndashve at the ndashve electrodeelectrode

LightLightSolid Solid silver chloridesilver chloride decomposes to decomposes to silversilver metal and metal and

chlorinechlorine gas (decomposition of silver compounds gas (decomposition of silver compounds is the basis of photography development)is the basis of photography development)

Synthesis ReactionsSynthesis ReactionsEnergy releasedEnergy released

A synthesis or combination reaction A synthesis or combination reaction involves the combination of two or involves the combination of two or more pure substances When a more pure substances When a compound is formed from its compound is formed from its elements it is known as a elements it is known as a direct direct combination reactioncombination reaction These These reactions normally release energy reactions normally release energy

A + B A + B AB + energy AB + energy

Synthesis reactions - Synthesis reactions - examplesexamples

MagnesiumMagnesium burns in air ( burns in air (oxygenoxygen) to produce ) to produce magnesium oxidemagnesium oxide (light and heat energy (light and heat energy released)released)

HydrogenHydrogen and and oxygenoxygen combine in an combine in an explosive reaction to produce explosive reaction to produce waterwater (much (much energy released)energy released)

CopperCopper metal combines with yellow metal combines with yellow sulphursulphur when heated to produce when heated to produce copper (I) copper (I) sulphidesulphide (much heat energy is released) (much heat energy is released)

Decomposition and Decomposition and SynthesisSynthesis

Everyday ApplicationsEveryday ApplicationsDecompositionDecomposition

Air bags ndash sodium azide Air bags ndash sodium azide (NaN(NaN33) decomposes to ) decomposes to sodium and nitrogen gas by sodium and nitrogen gas by ignition with a detonating ignition with a detonating capcap

Limestone (primarily CaCOLimestone (primarily CaCO33) ) ndash decomposes to calcium ndash decomposes to calcium oxide and carbon dioxide by oxide and carbon dioxide by heating to make lime (CaO) heating to make lime (CaO) cement and glasscement and glass

Aluminium - the industrial Aluminium - the industrial process of electrolysing process of electrolysing aluminium oxide produces aluminium oxide produces aluminium metalaluminium metal

SynthesisSynthesis Rust ndash iron and oxygen Rust ndash iron and oxygen

combine in the presence of combine in the presence of water to form iron (III) oxidewater to form iron (III) oxide

Burning coke (primarily Burning coke (primarily carbon) is used as a fuel in carbon) is used as a fuel in smelting iron ore in a blast smelting iron ore in a blast furnace during the steel furnace during the steel making process making process

Pollutants - NO (nitric oxide Pollutants - NO (nitric oxide or nitrogen monoxide) and or nitrogen monoxide) and NO2 (nitrogen dioxide) are NO2 (nitrogen dioxide) are formed inside the formed inside the combustion chambers of cars combustion chambers of cars from nitrogen and oxygen from nitrogen and oxygen gasesgases

82 The Chemical Earth82 The Chemical Earth

Focus 5Focus 5

The properties of elements and The properties of elements and compounds are determined by compounds are determined by

their bonding and structuretheir bonding and structure

Properties of elements and Properties of elements and their compounds are very their compounds are very

differentdifferent8Fe(s) + S8Fe(s) + S88(s) + heat (s) + heat 8FeS(s) 8FeS(s)

substancsubstancee

colourcolour Melting Melting point point ((00C)C)

Boiling Boiling point point ((00C)C)

Density Density (gcm(gcm33))

magneticmagnetic

IronIron GreyGrey 15351535 27502750 7979 yesyes

SulphurSulphur YellowYellow 113113 445445 2121 nono

Iron (II) Iron (II) sulphidesulphide

Yellow-Yellow-goldgold

11941194 -- 484484 nono

Properties of elements Properties of elements compounds and mixtures compounds and mixtures

are very differentare very differentAluminiumAluminiumPhysical propertiesPhysical properties MP = 660MP = 66000CC Density = 27 gcmDensity = 27 gcm3 3

Conductivity = 378 x10Conductivity = 378 x1066 Smiddotm-1 Smiddotm-1 (20 degC)(20 degC)

Chemical propertiesChemical properties 4Al(s)+ 3O4Al(s)+ 3O22(g) (g) 2Al 2Al22OO33(s)(s) 2Al(s) + 6HCl(g) 2Al(s) + 6HCl(g) 2AlCl 2AlCl33(aq) (aq)

+ 3H+ 3H22(g)(g)

OxygenOxygenPhysical propertiesPhysical properties MP = -219MP = -21900CC Density = 00013 gcmDensity = 00013 gcm33

Conductivity = non-conductorConductivity = non-conductor

Bauxite ore Bauxite ore (Al(Al22OO33xHxH22O)O)Physical propertiesPhysical properties MP = 2045MP = 204500CC Density = 35-4 gcmDensity = 35-4 gcm33

Conductivity = non-conductorConductivity = non-conductor

Chemical propertiesChemical properties AlAl22OO33(s) + 2NaOH + 3H(s) + 2NaOH + 3H22O(l) O(l)

2Na[Al(OH)2Na[Al(OH)44](aq) (Bayer process)](aq) (Bayer process)

NB Bauxite is essentially an impure NB Bauxite is essentially an impure aluminium oxide The major aluminium oxide The major impurities include iron oxides impurities include iron oxides silicon dioxide and titanium silicon dioxide and titanium dioxide The impurities remain as dioxide The impurities remain as solids and do not react with solids and do not react with NaOH This process removes NaOH This process removes these impuritiesthese impurities

Structure of metalsStructure of metals

Metals can be described as three-Metals can be described as three-dimensional lattices of positive ions in a dimensional lattices of positive ions in a sea of delocalised electrons sea of delocalised electrons

Covalent BondingCovalent Bonding Covalent Molecular-strong Covalent Molecular-strong

bonds weak bonds weak intermolecular forces intermolecular forces holding molecules holding molecules togethertogether

Covalent Network-Covalent Network-covalent bonding lattice covalent bonding lattice that extends indefinitely that extends indefinitely throughout the crystalthroughout the crystal

Ionic bondingIonic bonding

No discreet molecules are formed in No discreet molecules are formed in ionic bonding due to electrostatic ionic bonding due to electrostatic forces holding the atoms together forces holding the atoms together They form a continuing 3D latticeThey form a continuing 3D lattice

-- --

-- -- --

--

-- --

---- --++

++

++

++++

++

++

++++++

Properties associated with Properties associated with bond typesbond types

Metallic bondingMetallic bonding High melting pointsHigh melting points-due to strong attraction between -due to strong attraction between

positively charged metal ions and delocalized positively charged metal ions and delocalized electrons The higher the valency the stronger the electrons The higher the valency the stronger the bond eg Cabond eg Ca2+2+ is stronger than K is stronger than K++

Good conductors of heat and electricityGood conductors of heat and electricity-due to the high -due to the high mobility of delocalized electrons Electrons enter and mobility of delocalized electrons Electrons enter and leave a metal easilyleave a metal easily

Malleable and ductileMalleable and ductile-due to delocalized electrons not -due to delocalized electrons not belonging to any particular metal atom Therefore one belonging to any particular metal atom Therefore one layer of ions can slide over another without disrupting layer of ions can slide over another without disrupting the bond between metal atoms The electrons and the bond between metal atoms The electrons and metal ions simply rearrangemetal ions simply rearrange

HardnessHardness- tend to be hard due to tightly packed atoms- tend to be hard due to tightly packed atoms

Properties associated with Properties associated with bond typesbond types

Ionic bondingIonic bonding High melting pointsHigh melting points-due to strong electrostatic attraction -due to strong electrostatic attraction

between anions and cationsbetween anions and cations

Non-conductors of electricity in solid stateNon-conductors of electricity in solid state-due to -due to oppositely charged particles which are in fixed positionsoppositely charged particles which are in fixed positions

Conductors in the liquid (molten) stateConductors in the liquid (molten) state-due to the ions -due to the ions being able to move freely through the liquidbeing able to move freely through the liquid

HardnessHardness-due to strong electrostatic attraction between -due to strong electrostatic attraction between oppositely charged particlesoppositely charged particles

BrittleBrittle-due to the fixed location of oppositely charged -due to the fixed location of oppositely charged particles Displacement of ions moves them closer to ions particles Displacement of ions moves them closer to ions of a similar charge which increases the repulsive forces of a similar charge which increases the repulsive forces along the fracturealong the fracture

Properties associated with Properties associated with bond typesbond types

Covalent molecular bondingCovalent molecular bonding Low melting pointsLow melting points-due to generally weak -due to generally weak

attractive forces between molecules There attractive forces between molecules There are exceptions to this rule (eg Iare exceptions to this rule (eg I22 melts at melts at 11411400C but decomposes at 1000C but decomposes at 100000C) C)

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

SoftSoft-due to weak forces existing between -due to weak forces existing between moleculesmolecules

Properties associated with Properties associated with bond typesbond types

Covalent Network bondingCovalent Network bonding Very high melting points and boiling Very high melting points and boiling

pointspoints-due to strong covalent bonding -due to strong covalent bonding which form rigid 3-D structureswhich form rigid 3-D structures

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

Extremely hardExtremely hard- due to strong covalent - due to strong covalent bonding which form rigid 3-D structuresbonding which form rigid 3-D structures

The Chemical EarthThe Chemical Earth

Compiled by Robert Slider (2006)

Please share this resource with others

Covalent BondingCovalent BondingCovalent bonds are formed between two atoms sharing electrons Covalent bonds are formed between two atoms sharing electrons

In covalent bonding there is no electrostatic attraction as in In covalent bonding there is no electrostatic attraction as in ionic bonding Atoms will lsquosharersquo a pair (single bond) or pairs ionic bonding Atoms will lsquosharersquo a pair (single bond) or pairs (double or triple bonds) of e- to gain a noble gas configuration (double or triple bonds) of e- to gain a noble gas configuration For exampleFor example

Cl with and electron configuration of (287) will covalently bond Cl with and electron configuration of (287) will covalently bond with another Cl of (287) or with H of (1) to form Clwith another Cl of (287) or with H of (1) to form Cl22 or HCl or HCl

In the examples of ClIn the examples of Cl22 and HCl all atoms have a full valence and HCl all atoms have a full valence shell due to the sharing of electrons Cl has 8 e- and H has 2 e- shell due to the sharing of electrons Cl has 8 e- and H has 2 e- These compounds then exist as individual particles or molecules These compounds then exist as individual particles or molecules and are known as and are known as covalent molecular substancescovalent molecular substances to distinguish to distinguish them from them from covalent latticescovalent lattices such as in silicon dioxide and such as in silicon dioxide and diamonddiamond

Other examples include water ammonia and carbon dioxideOther examples include water ammonia and carbon dioxide

Covalent BondingCovalent Bonding

Covalent bonding leads to the formation of Covalent bonding leads to the formation of discreet molecules (ie single units that discreet molecules (ie single units that are often weakly bonded together by are often weakly bonded together by intermolecular forcesintermolecular forces) More about these ) More about these and their properties in 825and their properties in 825

WaterWater ChloriChlorinene

HydrogeHydrogen n ChloriChloridede

Lewis Dot StructuresLewis Dot StructuresLewis dot structures are a Lewis dot structures are a

way of representing the way of representing the valence e- configuration valence e- configuration of an atom and show of an atom and show how valence e- are how valence e- are arranged in compoundsarranged in compounds

Lewis dot structures can Lewis dot structures can be used to show the be used to show the formation of ions but are formation of ions but are more commonly used to more commonly used to show covalent bondingshow covalent bonding

The compounds formed to The compounds formed to the right are methane the right are methane ammonia water and ammonia water and hydrogen chloride hydrogen chloride (hydrochloric acid)(hydrochloric acid)

82 The Chemical Earth82 The Chemical Earth

Focus 4Focus 4

Energy is required to extract Energy is required to extract elements from their naturally elements from their naturally

occurring sourcesoccurring sources

Physical vs ChemicalPhysical vs Chemical Physical ndash changes that are associated with Physical ndash changes that are associated with

physical properties which do not change physical properties which do not change the chemical composition of a substancethe chemical composition of a substance Eg hardness density malleability ductility Eg hardness density malleability ductility

electrical and thermal conductivities melting electrical and thermal conductivities melting point boiling point solubilitypoint boiling point solubility

Chemical ndash changes that occur when a Chemical ndash changes that occur when a substance breaks down or reacts with substance breaks down or reacts with another substance in a chemical reactionanother substance in a chemical reaction A new substance is always formed and has A new substance is always formed and has

different properties than the original reactantsdifferent properties than the original reactants

Physical Changes - Physical Changes - examplesexamples

Changing of state (melting iron boiling water)Changing of state (melting iron boiling water) Changing the physical appearance (crushing Changing the physical appearance (crushing

ore in a ball mill drawing copper into wires)ore in a ball mill drawing copper into wires) Dissolving a solid in a liquid (sugar into Dissolving a solid in a liquid (sugar into

water)water) Separation of mixtures (filtering sand from Separation of mixtures (filtering sand from

water separating sea salt from water)water separating sea salt from water)

Physical changes ndash no new substancesPhysical changes ndash no new substances

Chemical Changes - Chemical Changes - indicationsindications

A gas is evolved (iron and HCl generate HA gas is evolved (iron and HCl generate H22 gas) gas) A solid (precipitate) is formed when two A solid (precipitate) is formed when two

solutions are added together (silver nitrate and solutions are added together (silver nitrate and sodium chloride solutions produce a white solid sodium chloride solutions produce a white solid of silver chloride)of silver chloride)

A change in colour (purple potassium A change in colour (purple potassium permanganate (permanganate (KMnO4KMnO4) is added to hydrogen ) is added to hydrogen peroxide the solution turns colourless)peroxide the solution turns colourless)

Change of temperature (magnesium is burned Change of temperature (magnesium is burned in air and becomes very hot)in air and becomes very hot)

Chemical change ndash at least one new Chemical change ndash at least one new substancesubstance

Physical vs Chemical -Physical vs Chemical -WaterWater

Water- a physical Water- a physical changechange

Boiling water is an example Boiling water is an example of relatively weak of relatively weak intermolecular forces intermolecular forces (Hydrogen bonds) (Hydrogen bonds) breakingbreaking

Energy required = 44 kJmolEnergy required = 44 kJmol

Water-a chemical Water-a chemical changechange

Electrolysis of water involves Electrolysis of water involves the breaking of very the breaking of very strong covalent bonds strong covalent bonds between H and O atomsbetween H and O atoms

Energy required = 286 Energy required = 286 kJmolkJmol

Physical vs Chemical -Physical vs Chemical -WaterWater

Boiling ndash breaking H Boiling ndash breaking H bondsbonds

Electrolysis ndash Electrolysis ndash breaking covalent breaking covalent bondsbonds

OOHH

HHHHHH

OOHH

HH

OOHH

HH

OOHH

HH

OOHH

HH

H bondH bond

OO

OO

OOHH

HH

++++

HHHH

Physical vs Chemical -Physical vs Chemical -summarysummary

Chemical changeChemical change

(reaction)(reaction)Physical changePhysical change

At least one new At least one new substance is formedsubstance is formed

No new substances No new substances are formedare formed

Difficult to reverse Difficult to reverse (eg unboiled egg)(eg unboiled egg)

Easily reversed (eg Easily reversed (eg melt ice and freeze it melt ice and freeze it again)again)

Generally requires a Generally requires a large amount of large amount of energyenergy

Generally relatively Generally relatively small quantities of small quantities of energyenergy

Decomposition ReactionsDecomposition Reactions Energy absorbed Energy absorbed

When a compound decomposes into When a compound decomposes into two or more other pure substances two or more other pure substances energy is normally absorbed in the energy is normally absorbed in the form of heat light or electricityform of heat light or electricity

+ AB + AB A + B A + BHeatHeat

LightLight

ElectricityElectricity

Decomposition Reactions-Decomposition Reactions-examplesexamples

HeatHeatSolid Solid copper nitratecopper nitrate decomposes to solid decomposes to solid copper copper

oxideoxide nitrogen dioxidenitrogen dioxide and and oxygenoxygen gases gases

ElectricityElectricityMolten Molten lead bromidelead bromide (400 (40000C) forms C) forms brominebromine gas at gas at

the +ve electrode and liquid the +ve electrode and liquid leadlead at the ndashve at the ndashve electrodeelectrode

LightLightSolid Solid silver chloridesilver chloride decomposes to decomposes to silversilver metal and metal and

chlorinechlorine gas (decomposition of silver compounds gas (decomposition of silver compounds is the basis of photography development)is the basis of photography development)

Synthesis ReactionsSynthesis ReactionsEnergy releasedEnergy released

A synthesis or combination reaction A synthesis or combination reaction involves the combination of two or involves the combination of two or more pure substances When a more pure substances When a compound is formed from its compound is formed from its elements it is known as a elements it is known as a direct direct combination reactioncombination reaction These These reactions normally release energy reactions normally release energy

A + B A + B AB + energy AB + energy

Synthesis reactions - Synthesis reactions - examplesexamples

MagnesiumMagnesium burns in air ( burns in air (oxygenoxygen) to produce ) to produce magnesium oxidemagnesium oxide (light and heat energy (light and heat energy released)released)

HydrogenHydrogen and and oxygenoxygen combine in an combine in an explosive reaction to produce explosive reaction to produce waterwater (much (much energy released)energy released)

CopperCopper metal combines with yellow metal combines with yellow sulphursulphur when heated to produce when heated to produce copper (I) copper (I) sulphidesulphide (much heat energy is released) (much heat energy is released)

Decomposition and Decomposition and SynthesisSynthesis

Everyday ApplicationsEveryday ApplicationsDecompositionDecomposition

Air bags ndash sodium azide Air bags ndash sodium azide (NaN(NaN33) decomposes to ) decomposes to sodium and nitrogen gas by sodium and nitrogen gas by ignition with a detonating ignition with a detonating capcap

Limestone (primarily CaCOLimestone (primarily CaCO33) ) ndash decomposes to calcium ndash decomposes to calcium oxide and carbon dioxide by oxide and carbon dioxide by heating to make lime (CaO) heating to make lime (CaO) cement and glasscement and glass

Aluminium - the industrial Aluminium - the industrial process of electrolysing process of electrolysing aluminium oxide produces aluminium oxide produces aluminium metalaluminium metal

SynthesisSynthesis Rust ndash iron and oxygen Rust ndash iron and oxygen

combine in the presence of combine in the presence of water to form iron (III) oxidewater to form iron (III) oxide

Burning coke (primarily Burning coke (primarily carbon) is used as a fuel in carbon) is used as a fuel in smelting iron ore in a blast smelting iron ore in a blast furnace during the steel furnace during the steel making process making process

Pollutants - NO (nitric oxide Pollutants - NO (nitric oxide or nitrogen monoxide) and or nitrogen monoxide) and NO2 (nitrogen dioxide) are NO2 (nitrogen dioxide) are formed inside the formed inside the combustion chambers of cars combustion chambers of cars from nitrogen and oxygen from nitrogen and oxygen gasesgases

82 The Chemical Earth82 The Chemical Earth

Focus 5Focus 5

The properties of elements and The properties of elements and compounds are determined by compounds are determined by

their bonding and structuretheir bonding and structure

Properties of elements and Properties of elements and their compounds are very their compounds are very

differentdifferent8Fe(s) + S8Fe(s) + S88(s) + heat (s) + heat 8FeS(s) 8FeS(s)

substancsubstancee

colourcolour Melting Melting point point ((00C)C)

Boiling Boiling point point ((00C)C)

Density Density (gcm(gcm33))

magneticmagnetic

IronIron GreyGrey 15351535 27502750 7979 yesyes

SulphurSulphur YellowYellow 113113 445445 2121 nono

Iron (II) Iron (II) sulphidesulphide

Yellow-Yellow-goldgold

11941194 -- 484484 nono

Properties of elements Properties of elements compounds and mixtures compounds and mixtures

are very differentare very differentAluminiumAluminiumPhysical propertiesPhysical properties MP = 660MP = 66000CC Density = 27 gcmDensity = 27 gcm3 3

Conductivity = 378 x10Conductivity = 378 x1066 Smiddotm-1 Smiddotm-1 (20 degC)(20 degC)

Chemical propertiesChemical properties 4Al(s)+ 3O4Al(s)+ 3O22(g) (g) 2Al 2Al22OO33(s)(s) 2Al(s) + 6HCl(g) 2Al(s) + 6HCl(g) 2AlCl 2AlCl33(aq) (aq)

+ 3H+ 3H22(g)(g)

OxygenOxygenPhysical propertiesPhysical properties MP = -219MP = -21900CC Density = 00013 gcmDensity = 00013 gcm33

Conductivity = non-conductorConductivity = non-conductor

Bauxite ore Bauxite ore (Al(Al22OO33xHxH22O)O)Physical propertiesPhysical properties MP = 2045MP = 204500CC Density = 35-4 gcmDensity = 35-4 gcm33

Conductivity = non-conductorConductivity = non-conductor

Chemical propertiesChemical properties AlAl22OO33(s) + 2NaOH + 3H(s) + 2NaOH + 3H22O(l) O(l)

2Na[Al(OH)2Na[Al(OH)44](aq) (Bayer process)](aq) (Bayer process)

NB Bauxite is essentially an impure NB Bauxite is essentially an impure aluminium oxide The major aluminium oxide The major impurities include iron oxides impurities include iron oxides silicon dioxide and titanium silicon dioxide and titanium dioxide The impurities remain as dioxide The impurities remain as solids and do not react with solids and do not react with NaOH This process removes NaOH This process removes these impuritiesthese impurities

Structure of metalsStructure of metals

Metals can be described as three-Metals can be described as three-dimensional lattices of positive ions in a dimensional lattices of positive ions in a sea of delocalised electrons sea of delocalised electrons

Covalent BondingCovalent Bonding Covalent Molecular-strong Covalent Molecular-strong

bonds weak bonds weak intermolecular forces intermolecular forces holding molecules holding molecules togethertogether

Covalent Network-Covalent Network-covalent bonding lattice covalent bonding lattice that extends indefinitely that extends indefinitely throughout the crystalthroughout the crystal

Ionic bondingIonic bonding

No discreet molecules are formed in No discreet molecules are formed in ionic bonding due to electrostatic ionic bonding due to electrostatic forces holding the atoms together forces holding the atoms together They form a continuing 3D latticeThey form a continuing 3D lattice

-- --

-- -- --

--

-- --

---- --++

++

++

++++

++

++

++++++

Properties associated with Properties associated with bond typesbond types

Metallic bondingMetallic bonding High melting pointsHigh melting points-due to strong attraction between -due to strong attraction between

positively charged metal ions and delocalized positively charged metal ions and delocalized electrons The higher the valency the stronger the electrons The higher the valency the stronger the bond eg Cabond eg Ca2+2+ is stronger than K is stronger than K++

Good conductors of heat and electricityGood conductors of heat and electricity-due to the high -due to the high mobility of delocalized electrons Electrons enter and mobility of delocalized electrons Electrons enter and leave a metal easilyleave a metal easily

Malleable and ductileMalleable and ductile-due to delocalized electrons not -due to delocalized electrons not belonging to any particular metal atom Therefore one belonging to any particular metal atom Therefore one layer of ions can slide over another without disrupting layer of ions can slide over another without disrupting the bond between metal atoms The electrons and the bond between metal atoms The electrons and metal ions simply rearrangemetal ions simply rearrange

HardnessHardness- tend to be hard due to tightly packed atoms- tend to be hard due to tightly packed atoms

Properties associated with Properties associated with bond typesbond types

Ionic bondingIonic bonding High melting pointsHigh melting points-due to strong electrostatic attraction -due to strong electrostatic attraction

between anions and cationsbetween anions and cations

Non-conductors of electricity in solid stateNon-conductors of electricity in solid state-due to -due to oppositely charged particles which are in fixed positionsoppositely charged particles which are in fixed positions

Conductors in the liquid (molten) stateConductors in the liquid (molten) state-due to the ions -due to the ions being able to move freely through the liquidbeing able to move freely through the liquid

HardnessHardness-due to strong electrostatic attraction between -due to strong electrostatic attraction between oppositely charged particlesoppositely charged particles

BrittleBrittle-due to the fixed location of oppositely charged -due to the fixed location of oppositely charged particles Displacement of ions moves them closer to ions particles Displacement of ions moves them closer to ions of a similar charge which increases the repulsive forces of a similar charge which increases the repulsive forces along the fracturealong the fracture

Properties associated with Properties associated with bond typesbond types

Covalent molecular bondingCovalent molecular bonding Low melting pointsLow melting points-due to generally weak -due to generally weak

attractive forces between molecules There attractive forces between molecules There are exceptions to this rule (eg Iare exceptions to this rule (eg I22 melts at melts at 11411400C but decomposes at 1000C but decomposes at 100000C) C)

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

SoftSoft-due to weak forces existing between -due to weak forces existing between moleculesmolecules

Properties associated with Properties associated with bond typesbond types

Covalent Network bondingCovalent Network bonding Very high melting points and boiling Very high melting points and boiling

pointspoints-due to strong covalent bonding -due to strong covalent bonding which form rigid 3-D structureswhich form rigid 3-D structures

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

Extremely hardExtremely hard- due to strong covalent - due to strong covalent bonding which form rigid 3-D structuresbonding which form rigid 3-D structures

The Chemical EarthThe Chemical Earth

Compiled by Robert Slider (2006)

Please share this resource with others

Covalent BondingCovalent Bonding

Covalent bonding leads to the formation of Covalent bonding leads to the formation of discreet molecules (ie single units that discreet molecules (ie single units that are often weakly bonded together by are often weakly bonded together by intermolecular forcesintermolecular forces) More about these ) More about these and their properties in 825and their properties in 825

WaterWater ChloriChlorinene

HydrogeHydrogen n ChloriChloridede

Lewis Dot StructuresLewis Dot StructuresLewis dot structures are a Lewis dot structures are a

way of representing the way of representing the valence e- configuration valence e- configuration of an atom and show of an atom and show how valence e- are how valence e- are arranged in compoundsarranged in compounds

Lewis dot structures can Lewis dot structures can be used to show the be used to show the formation of ions but are formation of ions but are more commonly used to more commonly used to show covalent bondingshow covalent bonding

The compounds formed to The compounds formed to the right are methane the right are methane ammonia water and ammonia water and hydrogen chloride hydrogen chloride (hydrochloric acid)(hydrochloric acid)

82 The Chemical Earth82 The Chemical Earth

Focus 4Focus 4

Energy is required to extract Energy is required to extract elements from their naturally elements from their naturally

occurring sourcesoccurring sources

Physical vs ChemicalPhysical vs Chemical Physical ndash changes that are associated with Physical ndash changes that are associated with

physical properties which do not change physical properties which do not change the chemical composition of a substancethe chemical composition of a substance Eg hardness density malleability ductility Eg hardness density malleability ductility

electrical and thermal conductivities melting electrical and thermal conductivities melting point boiling point solubilitypoint boiling point solubility

Chemical ndash changes that occur when a Chemical ndash changes that occur when a substance breaks down or reacts with substance breaks down or reacts with another substance in a chemical reactionanother substance in a chemical reaction A new substance is always formed and has A new substance is always formed and has

different properties than the original reactantsdifferent properties than the original reactants

Physical Changes - Physical Changes - examplesexamples

Changing of state (melting iron boiling water)Changing of state (melting iron boiling water) Changing the physical appearance (crushing Changing the physical appearance (crushing

ore in a ball mill drawing copper into wires)ore in a ball mill drawing copper into wires) Dissolving a solid in a liquid (sugar into Dissolving a solid in a liquid (sugar into

water)water) Separation of mixtures (filtering sand from Separation of mixtures (filtering sand from

water separating sea salt from water)water separating sea salt from water)

Physical changes ndash no new substancesPhysical changes ndash no new substances

Chemical Changes - Chemical Changes - indicationsindications

A gas is evolved (iron and HCl generate HA gas is evolved (iron and HCl generate H22 gas) gas) A solid (precipitate) is formed when two A solid (precipitate) is formed when two

solutions are added together (silver nitrate and solutions are added together (silver nitrate and sodium chloride solutions produce a white solid sodium chloride solutions produce a white solid of silver chloride)of silver chloride)

A change in colour (purple potassium A change in colour (purple potassium permanganate (permanganate (KMnO4KMnO4) is added to hydrogen ) is added to hydrogen peroxide the solution turns colourless)peroxide the solution turns colourless)

Change of temperature (magnesium is burned Change of temperature (magnesium is burned in air and becomes very hot)in air and becomes very hot)

Chemical change ndash at least one new Chemical change ndash at least one new substancesubstance

Physical vs Chemical -Physical vs Chemical -WaterWater

Water- a physical Water- a physical changechange

Boiling water is an example Boiling water is an example of relatively weak of relatively weak intermolecular forces intermolecular forces (Hydrogen bonds) (Hydrogen bonds) breakingbreaking

Energy required = 44 kJmolEnergy required = 44 kJmol

Water-a chemical Water-a chemical changechange

Electrolysis of water involves Electrolysis of water involves the breaking of very the breaking of very strong covalent bonds strong covalent bonds between H and O atomsbetween H and O atoms

Energy required = 286 Energy required = 286 kJmolkJmol

Physical vs Chemical -Physical vs Chemical -WaterWater

Boiling ndash breaking H Boiling ndash breaking H bondsbonds

Electrolysis ndash Electrolysis ndash breaking covalent breaking covalent bondsbonds

OOHH

HHHHHH

OOHH

HH

OOHH

HH

OOHH

HH

OOHH

HH

H bondH bond

OO

OO

OOHH

HH

++++

HHHH

Physical vs Chemical -Physical vs Chemical -summarysummary

Chemical changeChemical change

(reaction)(reaction)Physical changePhysical change

At least one new At least one new substance is formedsubstance is formed

No new substances No new substances are formedare formed

Difficult to reverse Difficult to reverse (eg unboiled egg)(eg unboiled egg)

Easily reversed (eg Easily reversed (eg melt ice and freeze it melt ice and freeze it again)again)

Generally requires a Generally requires a large amount of large amount of energyenergy

Generally relatively Generally relatively small quantities of small quantities of energyenergy

Decomposition ReactionsDecomposition Reactions Energy absorbed Energy absorbed

When a compound decomposes into When a compound decomposes into two or more other pure substances two or more other pure substances energy is normally absorbed in the energy is normally absorbed in the form of heat light or electricityform of heat light or electricity

+ AB + AB A + B A + BHeatHeat

LightLight

ElectricityElectricity

Decomposition Reactions-Decomposition Reactions-examplesexamples

HeatHeatSolid Solid copper nitratecopper nitrate decomposes to solid decomposes to solid copper copper

oxideoxide nitrogen dioxidenitrogen dioxide and and oxygenoxygen gases gases

ElectricityElectricityMolten Molten lead bromidelead bromide (400 (40000C) forms C) forms brominebromine gas at gas at

the +ve electrode and liquid the +ve electrode and liquid leadlead at the ndashve at the ndashve electrodeelectrode

LightLightSolid Solid silver chloridesilver chloride decomposes to decomposes to silversilver metal and metal and

chlorinechlorine gas (decomposition of silver compounds gas (decomposition of silver compounds is the basis of photography development)is the basis of photography development)

Synthesis ReactionsSynthesis ReactionsEnergy releasedEnergy released

A synthesis or combination reaction A synthesis or combination reaction involves the combination of two or involves the combination of two or more pure substances When a more pure substances When a compound is formed from its compound is formed from its elements it is known as a elements it is known as a direct direct combination reactioncombination reaction These These reactions normally release energy reactions normally release energy

A + B A + B AB + energy AB + energy

Synthesis reactions - Synthesis reactions - examplesexamples

MagnesiumMagnesium burns in air ( burns in air (oxygenoxygen) to produce ) to produce magnesium oxidemagnesium oxide (light and heat energy (light and heat energy released)released)

HydrogenHydrogen and and oxygenoxygen combine in an combine in an explosive reaction to produce explosive reaction to produce waterwater (much (much energy released)energy released)

CopperCopper metal combines with yellow metal combines with yellow sulphursulphur when heated to produce when heated to produce copper (I) copper (I) sulphidesulphide (much heat energy is released) (much heat energy is released)

Decomposition and Decomposition and SynthesisSynthesis

Everyday ApplicationsEveryday ApplicationsDecompositionDecomposition

Air bags ndash sodium azide Air bags ndash sodium azide (NaN(NaN33) decomposes to ) decomposes to sodium and nitrogen gas by sodium and nitrogen gas by ignition with a detonating ignition with a detonating capcap

Limestone (primarily CaCOLimestone (primarily CaCO33) ) ndash decomposes to calcium ndash decomposes to calcium oxide and carbon dioxide by oxide and carbon dioxide by heating to make lime (CaO) heating to make lime (CaO) cement and glasscement and glass

Aluminium - the industrial Aluminium - the industrial process of electrolysing process of electrolysing aluminium oxide produces aluminium oxide produces aluminium metalaluminium metal

SynthesisSynthesis Rust ndash iron and oxygen Rust ndash iron and oxygen

combine in the presence of combine in the presence of water to form iron (III) oxidewater to form iron (III) oxide

Burning coke (primarily Burning coke (primarily carbon) is used as a fuel in carbon) is used as a fuel in smelting iron ore in a blast smelting iron ore in a blast furnace during the steel furnace during the steel making process making process

Pollutants - NO (nitric oxide Pollutants - NO (nitric oxide or nitrogen monoxide) and or nitrogen monoxide) and NO2 (nitrogen dioxide) are NO2 (nitrogen dioxide) are formed inside the formed inside the combustion chambers of cars combustion chambers of cars from nitrogen and oxygen from nitrogen and oxygen gasesgases

82 The Chemical Earth82 The Chemical Earth

Focus 5Focus 5

The properties of elements and The properties of elements and compounds are determined by compounds are determined by

their bonding and structuretheir bonding and structure

Properties of elements and Properties of elements and their compounds are very their compounds are very

differentdifferent8Fe(s) + S8Fe(s) + S88(s) + heat (s) + heat 8FeS(s) 8FeS(s)

substancsubstancee

colourcolour Melting Melting point point ((00C)C)

Boiling Boiling point point ((00C)C)

Density Density (gcm(gcm33))

magneticmagnetic

IronIron GreyGrey 15351535 27502750 7979 yesyes

SulphurSulphur YellowYellow 113113 445445 2121 nono

Iron (II) Iron (II) sulphidesulphide

Yellow-Yellow-goldgold

11941194 -- 484484 nono

Properties of elements Properties of elements compounds and mixtures compounds and mixtures

are very differentare very differentAluminiumAluminiumPhysical propertiesPhysical properties MP = 660MP = 66000CC Density = 27 gcmDensity = 27 gcm3 3

Conductivity = 378 x10Conductivity = 378 x1066 Smiddotm-1 Smiddotm-1 (20 degC)(20 degC)

Chemical propertiesChemical properties 4Al(s)+ 3O4Al(s)+ 3O22(g) (g) 2Al 2Al22OO33(s)(s) 2Al(s) + 6HCl(g) 2Al(s) + 6HCl(g) 2AlCl 2AlCl33(aq) (aq)

+ 3H+ 3H22(g)(g)

OxygenOxygenPhysical propertiesPhysical properties MP = -219MP = -21900CC Density = 00013 gcmDensity = 00013 gcm33

Conductivity = non-conductorConductivity = non-conductor

Bauxite ore Bauxite ore (Al(Al22OO33xHxH22O)O)Physical propertiesPhysical properties MP = 2045MP = 204500CC Density = 35-4 gcmDensity = 35-4 gcm33

Conductivity = non-conductorConductivity = non-conductor

Chemical propertiesChemical properties AlAl22OO33(s) + 2NaOH + 3H(s) + 2NaOH + 3H22O(l) O(l)

2Na[Al(OH)2Na[Al(OH)44](aq) (Bayer process)](aq) (Bayer process)

NB Bauxite is essentially an impure NB Bauxite is essentially an impure aluminium oxide The major aluminium oxide The major impurities include iron oxides impurities include iron oxides silicon dioxide and titanium silicon dioxide and titanium dioxide The impurities remain as dioxide The impurities remain as solids and do not react with solids and do not react with NaOH This process removes NaOH This process removes these impuritiesthese impurities

Structure of metalsStructure of metals

Metals can be described as three-Metals can be described as three-dimensional lattices of positive ions in a dimensional lattices of positive ions in a sea of delocalised electrons sea of delocalised electrons

Covalent BondingCovalent Bonding Covalent Molecular-strong Covalent Molecular-strong

bonds weak bonds weak intermolecular forces intermolecular forces holding molecules holding molecules togethertogether

Covalent Network-Covalent Network-covalent bonding lattice covalent bonding lattice that extends indefinitely that extends indefinitely throughout the crystalthroughout the crystal

Ionic bondingIonic bonding

No discreet molecules are formed in No discreet molecules are formed in ionic bonding due to electrostatic ionic bonding due to electrostatic forces holding the atoms together forces holding the atoms together They form a continuing 3D latticeThey form a continuing 3D lattice

-- --

-- -- --

--

-- --

---- --++

++

++

++++

++

++

++++++

Properties associated with Properties associated with bond typesbond types

Metallic bondingMetallic bonding High melting pointsHigh melting points-due to strong attraction between -due to strong attraction between

positively charged metal ions and delocalized positively charged metal ions and delocalized electrons The higher the valency the stronger the electrons The higher the valency the stronger the bond eg Cabond eg Ca2+2+ is stronger than K is stronger than K++

Good conductors of heat and electricityGood conductors of heat and electricity-due to the high -due to the high mobility of delocalized electrons Electrons enter and mobility of delocalized electrons Electrons enter and leave a metal easilyleave a metal easily

Malleable and ductileMalleable and ductile-due to delocalized electrons not -due to delocalized electrons not belonging to any particular metal atom Therefore one belonging to any particular metal atom Therefore one layer of ions can slide over another without disrupting layer of ions can slide over another without disrupting the bond between metal atoms The electrons and the bond between metal atoms The electrons and metal ions simply rearrangemetal ions simply rearrange

HardnessHardness- tend to be hard due to tightly packed atoms- tend to be hard due to tightly packed atoms

Properties associated with Properties associated with bond typesbond types

Ionic bondingIonic bonding High melting pointsHigh melting points-due to strong electrostatic attraction -due to strong electrostatic attraction

between anions and cationsbetween anions and cations

Non-conductors of electricity in solid stateNon-conductors of electricity in solid state-due to -due to oppositely charged particles which are in fixed positionsoppositely charged particles which are in fixed positions

Conductors in the liquid (molten) stateConductors in the liquid (molten) state-due to the ions -due to the ions being able to move freely through the liquidbeing able to move freely through the liquid

HardnessHardness-due to strong electrostatic attraction between -due to strong electrostatic attraction between oppositely charged particlesoppositely charged particles

BrittleBrittle-due to the fixed location of oppositely charged -due to the fixed location of oppositely charged particles Displacement of ions moves them closer to ions particles Displacement of ions moves them closer to ions of a similar charge which increases the repulsive forces of a similar charge which increases the repulsive forces along the fracturealong the fracture

Properties associated with Properties associated with bond typesbond types

Covalent molecular bondingCovalent molecular bonding Low melting pointsLow melting points-due to generally weak -due to generally weak

attractive forces between molecules There attractive forces between molecules There are exceptions to this rule (eg Iare exceptions to this rule (eg I22 melts at melts at 11411400C but decomposes at 1000C but decomposes at 100000C) C)

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

SoftSoft-due to weak forces existing between -due to weak forces existing between moleculesmolecules

Properties associated with Properties associated with bond typesbond types

Covalent Network bondingCovalent Network bonding Very high melting points and boiling Very high melting points and boiling

pointspoints-due to strong covalent bonding -due to strong covalent bonding which form rigid 3-D structureswhich form rigid 3-D structures

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

Extremely hardExtremely hard- due to strong covalent - due to strong covalent bonding which form rigid 3-D structuresbonding which form rigid 3-D structures

The Chemical EarthThe Chemical Earth

Compiled by Robert Slider (2006)

Please share this resource with others

Lewis Dot StructuresLewis Dot StructuresLewis dot structures are a Lewis dot structures are a

way of representing the way of representing the valence e- configuration valence e- configuration of an atom and show of an atom and show how valence e- are how valence e- are arranged in compoundsarranged in compounds

Lewis dot structures can Lewis dot structures can be used to show the be used to show the formation of ions but are formation of ions but are more commonly used to more commonly used to show covalent bondingshow covalent bonding

The compounds formed to The compounds formed to the right are methane the right are methane ammonia water and ammonia water and hydrogen chloride hydrogen chloride (hydrochloric acid)(hydrochloric acid)

82 The Chemical Earth82 The Chemical Earth

Focus 4Focus 4

Energy is required to extract Energy is required to extract elements from their naturally elements from their naturally

occurring sourcesoccurring sources

Physical vs ChemicalPhysical vs Chemical Physical ndash changes that are associated with Physical ndash changes that are associated with

physical properties which do not change physical properties which do not change the chemical composition of a substancethe chemical composition of a substance Eg hardness density malleability ductility Eg hardness density malleability ductility

electrical and thermal conductivities melting electrical and thermal conductivities melting point boiling point solubilitypoint boiling point solubility

Chemical ndash changes that occur when a Chemical ndash changes that occur when a substance breaks down or reacts with substance breaks down or reacts with another substance in a chemical reactionanother substance in a chemical reaction A new substance is always formed and has A new substance is always formed and has

different properties than the original reactantsdifferent properties than the original reactants

Physical Changes - Physical Changes - examplesexamples

Changing of state (melting iron boiling water)Changing of state (melting iron boiling water) Changing the physical appearance (crushing Changing the physical appearance (crushing

ore in a ball mill drawing copper into wires)ore in a ball mill drawing copper into wires) Dissolving a solid in a liquid (sugar into Dissolving a solid in a liquid (sugar into

water)water) Separation of mixtures (filtering sand from Separation of mixtures (filtering sand from

water separating sea salt from water)water separating sea salt from water)

Physical changes ndash no new substancesPhysical changes ndash no new substances

Chemical Changes - Chemical Changes - indicationsindications

A gas is evolved (iron and HCl generate HA gas is evolved (iron and HCl generate H22 gas) gas) A solid (precipitate) is formed when two A solid (precipitate) is formed when two

solutions are added together (silver nitrate and solutions are added together (silver nitrate and sodium chloride solutions produce a white solid sodium chloride solutions produce a white solid of silver chloride)of silver chloride)

A change in colour (purple potassium A change in colour (purple potassium permanganate (permanganate (KMnO4KMnO4) is added to hydrogen ) is added to hydrogen peroxide the solution turns colourless)peroxide the solution turns colourless)

Change of temperature (magnesium is burned Change of temperature (magnesium is burned in air and becomes very hot)in air and becomes very hot)

Chemical change ndash at least one new Chemical change ndash at least one new substancesubstance

Physical vs Chemical -Physical vs Chemical -WaterWater

Water- a physical Water- a physical changechange

Boiling water is an example Boiling water is an example of relatively weak of relatively weak intermolecular forces intermolecular forces (Hydrogen bonds) (Hydrogen bonds) breakingbreaking

Energy required = 44 kJmolEnergy required = 44 kJmol

Water-a chemical Water-a chemical changechange

Electrolysis of water involves Electrolysis of water involves the breaking of very the breaking of very strong covalent bonds strong covalent bonds between H and O atomsbetween H and O atoms

Energy required = 286 Energy required = 286 kJmolkJmol

Physical vs Chemical -Physical vs Chemical -WaterWater

Boiling ndash breaking H Boiling ndash breaking H bondsbonds

Electrolysis ndash Electrolysis ndash breaking covalent breaking covalent bondsbonds

OOHH

HHHHHH

OOHH

HH

OOHH

HH

OOHH

HH

OOHH

HH

H bondH bond

OO

OO

OOHH

HH

++++

HHHH

Physical vs Chemical -Physical vs Chemical -summarysummary

Chemical changeChemical change

(reaction)(reaction)Physical changePhysical change

At least one new At least one new substance is formedsubstance is formed

No new substances No new substances are formedare formed

Difficult to reverse Difficult to reverse (eg unboiled egg)(eg unboiled egg)

Easily reversed (eg Easily reversed (eg melt ice and freeze it melt ice and freeze it again)again)

Generally requires a Generally requires a large amount of large amount of energyenergy

Generally relatively Generally relatively small quantities of small quantities of energyenergy

Decomposition ReactionsDecomposition Reactions Energy absorbed Energy absorbed

When a compound decomposes into When a compound decomposes into two or more other pure substances two or more other pure substances energy is normally absorbed in the energy is normally absorbed in the form of heat light or electricityform of heat light or electricity

+ AB + AB A + B A + BHeatHeat

LightLight

ElectricityElectricity

Decomposition Reactions-Decomposition Reactions-examplesexamples

HeatHeatSolid Solid copper nitratecopper nitrate decomposes to solid decomposes to solid copper copper

oxideoxide nitrogen dioxidenitrogen dioxide and and oxygenoxygen gases gases

ElectricityElectricityMolten Molten lead bromidelead bromide (400 (40000C) forms C) forms brominebromine gas at gas at

the +ve electrode and liquid the +ve electrode and liquid leadlead at the ndashve at the ndashve electrodeelectrode

LightLightSolid Solid silver chloridesilver chloride decomposes to decomposes to silversilver metal and metal and

chlorinechlorine gas (decomposition of silver compounds gas (decomposition of silver compounds is the basis of photography development)is the basis of photography development)

Synthesis ReactionsSynthesis ReactionsEnergy releasedEnergy released

A synthesis or combination reaction A synthesis or combination reaction involves the combination of two or involves the combination of two or more pure substances When a more pure substances When a compound is formed from its compound is formed from its elements it is known as a elements it is known as a direct direct combination reactioncombination reaction These These reactions normally release energy reactions normally release energy

A + B A + B AB + energy AB + energy

Synthesis reactions - Synthesis reactions - examplesexamples

MagnesiumMagnesium burns in air ( burns in air (oxygenoxygen) to produce ) to produce magnesium oxidemagnesium oxide (light and heat energy (light and heat energy released)released)

HydrogenHydrogen and and oxygenoxygen combine in an combine in an explosive reaction to produce explosive reaction to produce waterwater (much (much energy released)energy released)

CopperCopper metal combines with yellow metal combines with yellow sulphursulphur when heated to produce when heated to produce copper (I) copper (I) sulphidesulphide (much heat energy is released) (much heat energy is released)

Decomposition and Decomposition and SynthesisSynthesis

Everyday ApplicationsEveryday ApplicationsDecompositionDecomposition

Air bags ndash sodium azide Air bags ndash sodium azide (NaN(NaN33) decomposes to ) decomposes to sodium and nitrogen gas by sodium and nitrogen gas by ignition with a detonating ignition with a detonating capcap

Limestone (primarily CaCOLimestone (primarily CaCO33) ) ndash decomposes to calcium ndash decomposes to calcium oxide and carbon dioxide by oxide and carbon dioxide by heating to make lime (CaO) heating to make lime (CaO) cement and glasscement and glass

Aluminium - the industrial Aluminium - the industrial process of electrolysing process of electrolysing aluminium oxide produces aluminium oxide produces aluminium metalaluminium metal

SynthesisSynthesis Rust ndash iron and oxygen Rust ndash iron and oxygen

combine in the presence of combine in the presence of water to form iron (III) oxidewater to form iron (III) oxide

Burning coke (primarily Burning coke (primarily carbon) is used as a fuel in carbon) is used as a fuel in smelting iron ore in a blast smelting iron ore in a blast furnace during the steel furnace during the steel making process making process

Pollutants - NO (nitric oxide Pollutants - NO (nitric oxide or nitrogen monoxide) and or nitrogen monoxide) and NO2 (nitrogen dioxide) are NO2 (nitrogen dioxide) are formed inside the formed inside the combustion chambers of cars combustion chambers of cars from nitrogen and oxygen from nitrogen and oxygen gasesgases

82 The Chemical Earth82 The Chemical Earth

Focus 5Focus 5

The properties of elements and The properties of elements and compounds are determined by compounds are determined by

their bonding and structuretheir bonding and structure

Properties of elements and Properties of elements and their compounds are very their compounds are very

differentdifferent8Fe(s) + S8Fe(s) + S88(s) + heat (s) + heat 8FeS(s) 8FeS(s)

substancsubstancee

colourcolour Melting Melting point point ((00C)C)

Boiling Boiling point point ((00C)C)

Density Density (gcm(gcm33))

magneticmagnetic

IronIron GreyGrey 15351535 27502750 7979 yesyes

SulphurSulphur YellowYellow 113113 445445 2121 nono

Iron (II) Iron (II) sulphidesulphide

Yellow-Yellow-goldgold

11941194 -- 484484 nono

Properties of elements Properties of elements compounds and mixtures compounds and mixtures

are very differentare very differentAluminiumAluminiumPhysical propertiesPhysical properties MP = 660MP = 66000CC Density = 27 gcmDensity = 27 gcm3 3

Conductivity = 378 x10Conductivity = 378 x1066 Smiddotm-1 Smiddotm-1 (20 degC)(20 degC)

Chemical propertiesChemical properties 4Al(s)+ 3O4Al(s)+ 3O22(g) (g) 2Al 2Al22OO33(s)(s) 2Al(s) + 6HCl(g) 2Al(s) + 6HCl(g) 2AlCl 2AlCl33(aq) (aq)

+ 3H+ 3H22(g)(g)

OxygenOxygenPhysical propertiesPhysical properties MP = -219MP = -21900CC Density = 00013 gcmDensity = 00013 gcm33

Conductivity = non-conductorConductivity = non-conductor

Bauxite ore Bauxite ore (Al(Al22OO33xHxH22O)O)Physical propertiesPhysical properties MP = 2045MP = 204500CC Density = 35-4 gcmDensity = 35-4 gcm33

Conductivity = non-conductorConductivity = non-conductor

Chemical propertiesChemical properties AlAl22OO33(s) + 2NaOH + 3H(s) + 2NaOH + 3H22O(l) O(l)

2Na[Al(OH)2Na[Al(OH)44](aq) (Bayer process)](aq) (Bayer process)

NB Bauxite is essentially an impure NB Bauxite is essentially an impure aluminium oxide The major aluminium oxide The major impurities include iron oxides impurities include iron oxides silicon dioxide and titanium silicon dioxide and titanium dioxide The impurities remain as dioxide The impurities remain as solids and do not react with solids and do not react with NaOH This process removes NaOH This process removes these impuritiesthese impurities

Structure of metalsStructure of metals

Metals can be described as three-Metals can be described as three-dimensional lattices of positive ions in a dimensional lattices of positive ions in a sea of delocalised electrons sea of delocalised electrons

Covalent BondingCovalent Bonding Covalent Molecular-strong Covalent Molecular-strong

bonds weak bonds weak intermolecular forces intermolecular forces holding molecules holding molecules togethertogether

Covalent Network-Covalent Network-covalent bonding lattice covalent bonding lattice that extends indefinitely that extends indefinitely throughout the crystalthroughout the crystal

Ionic bondingIonic bonding

No discreet molecules are formed in No discreet molecules are formed in ionic bonding due to electrostatic ionic bonding due to electrostatic forces holding the atoms together forces holding the atoms together They form a continuing 3D latticeThey form a continuing 3D lattice

-- --

-- -- --

--

-- --

---- --++

++

++

++++

++

++

++++++

Properties associated with Properties associated with bond typesbond types

Metallic bondingMetallic bonding High melting pointsHigh melting points-due to strong attraction between -due to strong attraction between

positively charged metal ions and delocalized positively charged metal ions and delocalized electrons The higher the valency the stronger the electrons The higher the valency the stronger the bond eg Cabond eg Ca2+2+ is stronger than K is stronger than K++

Good conductors of heat and electricityGood conductors of heat and electricity-due to the high -due to the high mobility of delocalized electrons Electrons enter and mobility of delocalized electrons Electrons enter and leave a metal easilyleave a metal easily

Malleable and ductileMalleable and ductile-due to delocalized electrons not -due to delocalized electrons not belonging to any particular metal atom Therefore one belonging to any particular metal atom Therefore one layer of ions can slide over another without disrupting layer of ions can slide over another without disrupting the bond between metal atoms The electrons and the bond between metal atoms The electrons and metal ions simply rearrangemetal ions simply rearrange

HardnessHardness- tend to be hard due to tightly packed atoms- tend to be hard due to tightly packed atoms

Properties associated with Properties associated with bond typesbond types

Ionic bondingIonic bonding High melting pointsHigh melting points-due to strong electrostatic attraction -due to strong electrostatic attraction

between anions and cationsbetween anions and cations

Non-conductors of electricity in solid stateNon-conductors of electricity in solid state-due to -due to oppositely charged particles which are in fixed positionsoppositely charged particles which are in fixed positions

Conductors in the liquid (molten) stateConductors in the liquid (molten) state-due to the ions -due to the ions being able to move freely through the liquidbeing able to move freely through the liquid

HardnessHardness-due to strong electrostatic attraction between -due to strong electrostatic attraction between oppositely charged particlesoppositely charged particles

BrittleBrittle-due to the fixed location of oppositely charged -due to the fixed location of oppositely charged particles Displacement of ions moves them closer to ions particles Displacement of ions moves them closer to ions of a similar charge which increases the repulsive forces of a similar charge which increases the repulsive forces along the fracturealong the fracture

Properties associated with Properties associated with bond typesbond types

Covalent molecular bondingCovalent molecular bonding Low melting pointsLow melting points-due to generally weak -due to generally weak

attractive forces between molecules There attractive forces between molecules There are exceptions to this rule (eg Iare exceptions to this rule (eg I22 melts at melts at 11411400C but decomposes at 1000C but decomposes at 100000C) C)

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

SoftSoft-due to weak forces existing between -due to weak forces existing between moleculesmolecules

Properties associated with Properties associated with bond typesbond types

Covalent Network bondingCovalent Network bonding Very high melting points and boiling Very high melting points and boiling

pointspoints-due to strong covalent bonding -due to strong covalent bonding which form rigid 3-D structureswhich form rigid 3-D structures

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

Extremely hardExtremely hard- due to strong covalent - due to strong covalent bonding which form rigid 3-D structuresbonding which form rigid 3-D structures

The Chemical EarthThe Chemical Earth

Compiled by Robert Slider (2006)

Please share this resource with others

82 The Chemical Earth82 The Chemical Earth

Focus 4Focus 4

Energy is required to extract Energy is required to extract elements from their naturally elements from their naturally

occurring sourcesoccurring sources

Physical vs ChemicalPhysical vs Chemical Physical ndash changes that are associated with Physical ndash changes that are associated with

physical properties which do not change physical properties which do not change the chemical composition of a substancethe chemical composition of a substance Eg hardness density malleability ductility Eg hardness density malleability ductility

electrical and thermal conductivities melting electrical and thermal conductivities melting point boiling point solubilitypoint boiling point solubility

Chemical ndash changes that occur when a Chemical ndash changes that occur when a substance breaks down or reacts with substance breaks down or reacts with another substance in a chemical reactionanother substance in a chemical reaction A new substance is always formed and has A new substance is always formed and has

different properties than the original reactantsdifferent properties than the original reactants

Physical Changes - Physical Changes - examplesexamples

Changing of state (melting iron boiling water)Changing of state (melting iron boiling water) Changing the physical appearance (crushing Changing the physical appearance (crushing

ore in a ball mill drawing copper into wires)ore in a ball mill drawing copper into wires) Dissolving a solid in a liquid (sugar into Dissolving a solid in a liquid (sugar into

water)water) Separation of mixtures (filtering sand from Separation of mixtures (filtering sand from

water separating sea salt from water)water separating sea salt from water)

Physical changes ndash no new substancesPhysical changes ndash no new substances

Chemical Changes - Chemical Changes - indicationsindications

A gas is evolved (iron and HCl generate HA gas is evolved (iron and HCl generate H22 gas) gas) A solid (precipitate) is formed when two A solid (precipitate) is formed when two

solutions are added together (silver nitrate and solutions are added together (silver nitrate and sodium chloride solutions produce a white solid sodium chloride solutions produce a white solid of silver chloride)of silver chloride)

A change in colour (purple potassium A change in colour (purple potassium permanganate (permanganate (KMnO4KMnO4) is added to hydrogen ) is added to hydrogen peroxide the solution turns colourless)peroxide the solution turns colourless)

Change of temperature (magnesium is burned Change of temperature (magnesium is burned in air and becomes very hot)in air and becomes very hot)

Chemical change ndash at least one new Chemical change ndash at least one new substancesubstance

Physical vs Chemical -Physical vs Chemical -WaterWater

Water- a physical Water- a physical changechange

Boiling water is an example Boiling water is an example of relatively weak of relatively weak intermolecular forces intermolecular forces (Hydrogen bonds) (Hydrogen bonds) breakingbreaking

Energy required = 44 kJmolEnergy required = 44 kJmol

Water-a chemical Water-a chemical changechange

Electrolysis of water involves Electrolysis of water involves the breaking of very the breaking of very strong covalent bonds strong covalent bonds between H and O atomsbetween H and O atoms

Energy required = 286 Energy required = 286 kJmolkJmol

Physical vs Chemical -Physical vs Chemical -WaterWater

Boiling ndash breaking H Boiling ndash breaking H bondsbonds

Electrolysis ndash Electrolysis ndash breaking covalent breaking covalent bondsbonds

OOHH

HHHHHH

OOHH

HH

OOHH

HH

OOHH

HH

OOHH

HH

H bondH bond

OO

OO

OOHH

HH

++++

HHHH

Physical vs Chemical -Physical vs Chemical -summarysummary

Chemical changeChemical change

(reaction)(reaction)Physical changePhysical change

At least one new At least one new substance is formedsubstance is formed

No new substances No new substances are formedare formed

Difficult to reverse Difficult to reverse (eg unboiled egg)(eg unboiled egg)

Easily reversed (eg Easily reversed (eg melt ice and freeze it melt ice and freeze it again)again)

Generally requires a Generally requires a large amount of large amount of energyenergy

Generally relatively Generally relatively small quantities of small quantities of energyenergy

Decomposition ReactionsDecomposition Reactions Energy absorbed Energy absorbed

When a compound decomposes into When a compound decomposes into two or more other pure substances two or more other pure substances energy is normally absorbed in the energy is normally absorbed in the form of heat light or electricityform of heat light or electricity

+ AB + AB A + B A + BHeatHeat

LightLight

ElectricityElectricity

Decomposition Reactions-Decomposition Reactions-examplesexamples

HeatHeatSolid Solid copper nitratecopper nitrate decomposes to solid decomposes to solid copper copper

oxideoxide nitrogen dioxidenitrogen dioxide and and oxygenoxygen gases gases

ElectricityElectricityMolten Molten lead bromidelead bromide (400 (40000C) forms C) forms brominebromine gas at gas at

the +ve electrode and liquid the +ve electrode and liquid leadlead at the ndashve at the ndashve electrodeelectrode

LightLightSolid Solid silver chloridesilver chloride decomposes to decomposes to silversilver metal and metal and

chlorinechlorine gas (decomposition of silver compounds gas (decomposition of silver compounds is the basis of photography development)is the basis of photography development)

Synthesis ReactionsSynthesis ReactionsEnergy releasedEnergy released

A synthesis or combination reaction A synthesis or combination reaction involves the combination of two or involves the combination of two or more pure substances When a more pure substances When a compound is formed from its compound is formed from its elements it is known as a elements it is known as a direct direct combination reactioncombination reaction These These reactions normally release energy reactions normally release energy

A + B A + B AB + energy AB + energy

Synthesis reactions - Synthesis reactions - examplesexamples

MagnesiumMagnesium burns in air ( burns in air (oxygenoxygen) to produce ) to produce magnesium oxidemagnesium oxide (light and heat energy (light and heat energy released)released)

HydrogenHydrogen and and oxygenoxygen combine in an combine in an explosive reaction to produce explosive reaction to produce waterwater (much (much energy released)energy released)

CopperCopper metal combines with yellow metal combines with yellow sulphursulphur when heated to produce when heated to produce copper (I) copper (I) sulphidesulphide (much heat energy is released) (much heat energy is released)

Decomposition and Decomposition and SynthesisSynthesis

Everyday ApplicationsEveryday ApplicationsDecompositionDecomposition

Air bags ndash sodium azide Air bags ndash sodium azide (NaN(NaN33) decomposes to ) decomposes to sodium and nitrogen gas by sodium and nitrogen gas by ignition with a detonating ignition with a detonating capcap

Limestone (primarily CaCOLimestone (primarily CaCO33) ) ndash decomposes to calcium ndash decomposes to calcium oxide and carbon dioxide by oxide and carbon dioxide by heating to make lime (CaO) heating to make lime (CaO) cement and glasscement and glass

Aluminium - the industrial Aluminium - the industrial process of electrolysing process of electrolysing aluminium oxide produces aluminium oxide produces aluminium metalaluminium metal

SynthesisSynthesis Rust ndash iron and oxygen Rust ndash iron and oxygen

combine in the presence of combine in the presence of water to form iron (III) oxidewater to form iron (III) oxide

Burning coke (primarily Burning coke (primarily carbon) is used as a fuel in carbon) is used as a fuel in smelting iron ore in a blast smelting iron ore in a blast furnace during the steel furnace during the steel making process making process

Pollutants - NO (nitric oxide Pollutants - NO (nitric oxide or nitrogen monoxide) and or nitrogen monoxide) and NO2 (nitrogen dioxide) are NO2 (nitrogen dioxide) are formed inside the formed inside the combustion chambers of cars combustion chambers of cars from nitrogen and oxygen from nitrogen and oxygen gasesgases

82 The Chemical Earth82 The Chemical Earth

Focus 5Focus 5

The properties of elements and The properties of elements and compounds are determined by compounds are determined by

their bonding and structuretheir bonding and structure

Properties of elements and Properties of elements and their compounds are very their compounds are very

differentdifferent8Fe(s) + S8Fe(s) + S88(s) + heat (s) + heat 8FeS(s) 8FeS(s)

substancsubstancee

colourcolour Melting Melting point point ((00C)C)

Boiling Boiling point point ((00C)C)

Density Density (gcm(gcm33))

magneticmagnetic

IronIron GreyGrey 15351535 27502750 7979 yesyes

SulphurSulphur YellowYellow 113113 445445 2121 nono

Iron (II) Iron (II) sulphidesulphide

Yellow-Yellow-goldgold

11941194 -- 484484 nono

Properties of elements Properties of elements compounds and mixtures compounds and mixtures

are very differentare very differentAluminiumAluminiumPhysical propertiesPhysical properties MP = 660MP = 66000CC Density = 27 gcmDensity = 27 gcm3 3

Conductivity = 378 x10Conductivity = 378 x1066 Smiddotm-1 Smiddotm-1 (20 degC)(20 degC)

Chemical propertiesChemical properties 4Al(s)+ 3O4Al(s)+ 3O22(g) (g) 2Al 2Al22OO33(s)(s) 2Al(s) + 6HCl(g) 2Al(s) + 6HCl(g) 2AlCl 2AlCl33(aq) (aq)

+ 3H+ 3H22(g)(g)

OxygenOxygenPhysical propertiesPhysical properties MP = -219MP = -21900CC Density = 00013 gcmDensity = 00013 gcm33

Conductivity = non-conductorConductivity = non-conductor

Bauxite ore Bauxite ore (Al(Al22OO33xHxH22O)O)Physical propertiesPhysical properties MP = 2045MP = 204500CC Density = 35-4 gcmDensity = 35-4 gcm33

Conductivity = non-conductorConductivity = non-conductor

Chemical propertiesChemical properties AlAl22OO33(s) + 2NaOH + 3H(s) + 2NaOH + 3H22O(l) O(l)

2Na[Al(OH)2Na[Al(OH)44](aq) (Bayer process)](aq) (Bayer process)

NB Bauxite is essentially an impure NB Bauxite is essentially an impure aluminium oxide The major aluminium oxide The major impurities include iron oxides impurities include iron oxides silicon dioxide and titanium silicon dioxide and titanium dioxide The impurities remain as dioxide The impurities remain as solids and do not react with solids and do not react with NaOH This process removes NaOH This process removes these impuritiesthese impurities

Structure of metalsStructure of metals

Metals can be described as three-Metals can be described as three-dimensional lattices of positive ions in a dimensional lattices of positive ions in a sea of delocalised electrons sea of delocalised electrons

Covalent BondingCovalent Bonding Covalent Molecular-strong Covalent Molecular-strong

bonds weak bonds weak intermolecular forces intermolecular forces holding molecules holding molecules togethertogether

Covalent Network-Covalent Network-covalent bonding lattice covalent bonding lattice that extends indefinitely that extends indefinitely throughout the crystalthroughout the crystal

Ionic bondingIonic bonding

No discreet molecules are formed in No discreet molecules are formed in ionic bonding due to electrostatic ionic bonding due to electrostatic forces holding the atoms together forces holding the atoms together They form a continuing 3D latticeThey form a continuing 3D lattice

-- --

-- -- --

--

-- --

---- --++

++

++

++++

++

++

++++++

Properties associated with Properties associated with bond typesbond types

Metallic bondingMetallic bonding High melting pointsHigh melting points-due to strong attraction between -due to strong attraction between

positively charged metal ions and delocalized positively charged metal ions and delocalized electrons The higher the valency the stronger the electrons The higher the valency the stronger the bond eg Cabond eg Ca2+2+ is stronger than K is stronger than K++

Good conductors of heat and electricityGood conductors of heat and electricity-due to the high -due to the high mobility of delocalized electrons Electrons enter and mobility of delocalized electrons Electrons enter and leave a metal easilyleave a metal easily

Malleable and ductileMalleable and ductile-due to delocalized electrons not -due to delocalized electrons not belonging to any particular metal atom Therefore one belonging to any particular metal atom Therefore one layer of ions can slide over another without disrupting layer of ions can slide over another without disrupting the bond between metal atoms The electrons and the bond between metal atoms The electrons and metal ions simply rearrangemetal ions simply rearrange

HardnessHardness- tend to be hard due to tightly packed atoms- tend to be hard due to tightly packed atoms

Properties associated with Properties associated with bond typesbond types

Ionic bondingIonic bonding High melting pointsHigh melting points-due to strong electrostatic attraction -due to strong electrostatic attraction

between anions and cationsbetween anions and cations

Non-conductors of electricity in solid stateNon-conductors of electricity in solid state-due to -due to oppositely charged particles which are in fixed positionsoppositely charged particles which are in fixed positions

Conductors in the liquid (molten) stateConductors in the liquid (molten) state-due to the ions -due to the ions being able to move freely through the liquidbeing able to move freely through the liquid

HardnessHardness-due to strong electrostatic attraction between -due to strong electrostatic attraction between oppositely charged particlesoppositely charged particles

BrittleBrittle-due to the fixed location of oppositely charged -due to the fixed location of oppositely charged particles Displacement of ions moves them closer to ions particles Displacement of ions moves them closer to ions of a similar charge which increases the repulsive forces of a similar charge which increases the repulsive forces along the fracturealong the fracture

Properties associated with Properties associated with bond typesbond types

Covalent molecular bondingCovalent molecular bonding Low melting pointsLow melting points-due to generally weak -due to generally weak

attractive forces between molecules There attractive forces between molecules There are exceptions to this rule (eg Iare exceptions to this rule (eg I22 melts at melts at 11411400C but decomposes at 1000C but decomposes at 100000C) C)

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

SoftSoft-due to weak forces existing between -due to weak forces existing between moleculesmolecules

Properties associated with Properties associated with bond typesbond types

Covalent Network bondingCovalent Network bonding Very high melting points and boiling Very high melting points and boiling

pointspoints-due to strong covalent bonding -due to strong covalent bonding which form rigid 3-D structureswhich form rigid 3-D structures

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

Extremely hardExtremely hard- due to strong covalent - due to strong covalent bonding which form rigid 3-D structuresbonding which form rigid 3-D structures

The Chemical EarthThe Chemical Earth

Compiled by Robert Slider (2006)

Please share this resource with others

Physical vs ChemicalPhysical vs Chemical Physical ndash changes that are associated with Physical ndash changes that are associated with

physical properties which do not change physical properties which do not change the chemical composition of a substancethe chemical composition of a substance Eg hardness density malleability ductility Eg hardness density malleability ductility

electrical and thermal conductivities melting electrical and thermal conductivities melting point boiling point solubilitypoint boiling point solubility

Chemical ndash changes that occur when a Chemical ndash changes that occur when a substance breaks down or reacts with substance breaks down or reacts with another substance in a chemical reactionanother substance in a chemical reaction A new substance is always formed and has A new substance is always formed and has

different properties than the original reactantsdifferent properties than the original reactants

Physical Changes - Physical Changes - examplesexamples

Changing of state (melting iron boiling water)Changing of state (melting iron boiling water) Changing the physical appearance (crushing Changing the physical appearance (crushing

ore in a ball mill drawing copper into wires)ore in a ball mill drawing copper into wires) Dissolving a solid in a liquid (sugar into Dissolving a solid in a liquid (sugar into

water)water) Separation of mixtures (filtering sand from Separation of mixtures (filtering sand from

water separating sea salt from water)water separating sea salt from water)

Physical changes ndash no new substancesPhysical changes ndash no new substances

Chemical Changes - Chemical Changes - indicationsindications

A gas is evolved (iron and HCl generate HA gas is evolved (iron and HCl generate H22 gas) gas) A solid (precipitate) is formed when two A solid (precipitate) is formed when two

solutions are added together (silver nitrate and solutions are added together (silver nitrate and sodium chloride solutions produce a white solid sodium chloride solutions produce a white solid of silver chloride)of silver chloride)

A change in colour (purple potassium A change in colour (purple potassium permanganate (permanganate (KMnO4KMnO4) is added to hydrogen ) is added to hydrogen peroxide the solution turns colourless)peroxide the solution turns colourless)

Change of temperature (magnesium is burned Change of temperature (magnesium is burned in air and becomes very hot)in air and becomes very hot)

Chemical change ndash at least one new Chemical change ndash at least one new substancesubstance

Physical vs Chemical -Physical vs Chemical -WaterWater

Water- a physical Water- a physical changechange

Boiling water is an example Boiling water is an example of relatively weak of relatively weak intermolecular forces intermolecular forces (Hydrogen bonds) (Hydrogen bonds) breakingbreaking

Energy required = 44 kJmolEnergy required = 44 kJmol

Water-a chemical Water-a chemical changechange

Electrolysis of water involves Electrolysis of water involves the breaking of very the breaking of very strong covalent bonds strong covalent bonds between H and O atomsbetween H and O atoms

Energy required = 286 Energy required = 286 kJmolkJmol

Physical vs Chemical -Physical vs Chemical -WaterWater

Boiling ndash breaking H Boiling ndash breaking H bondsbonds

Electrolysis ndash Electrolysis ndash breaking covalent breaking covalent bondsbonds

OOHH

HHHHHH

OOHH

HH

OOHH

HH

OOHH

HH

OOHH

HH

H bondH bond

OO

OO

OOHH

HH

++++

HHHH

Physical vs Chemical -Physical vs Chemical -summarysummary

Chemical changeChemical change

(reaction)(reaction)Physical changePhysical change

At least one new At least one new substance is formedsubstance is formed

No new substances No new substances are formedare formed

Difficult to reverse Difficult to reverse (eg unboiled egg)(eg unboiled egg)

Easily reversed (eg Easily reversed (eg melt ice and freeze it melt ice and freeze it again)again)

Generally requires a Generally requires a large amount of large amount of energyenergy

Generally relatively Generally relatively small quantities of small quantities of energyenergy

Decomposition ReactionsDecomposition Reactions Energy absorbed Energy absorbed

When a compound decomposes into When a compound decomposes into two or more other pure substances two or more other pure substances energy is normally absorbed in the energy is normally absorbed in the form of heat light or electricityform of heat light or electricity

+ AB + AB A + B A + BHeatHeat

LightLight

ElectricityElectricity

Decomposition Reactions-Decomposition Reactions-examplesexamples

HeatHeatSolid Solid copper nitratecopper nitrate decomposes to solid decomposes to solid copper copper

oxideoxide nitrogen dioxidenitrogen dioxide and and oxygenoxygen gases gases

ElectricityElectricityMolten Molten lead bromidelead bromide (400 (40000C) forms C) forms brominebromine gas at gas at

the +ve electrode and liquid the +ve electrode and liquid leadlead at the ndashve at the ndashve electrodeelectrode

LightLightSolid Solid silver chloridesilver chloride decomposes to decomposes to silversilver metal and metal and

chlorinechlorine gas (decomposition of silver compounds gas (decomposition of silver compounds is the basis of photography development)is the basis of photography development)

Synthesis ReactionsSynthesis ReactionsEnergy releasedEnergy released

A synthesis or combination reaction A synthesis or combination reaction involves the combination of two or involves the combination of two or more pure substances When a more pure substances When a compound is formed from its compound is formed from its elements it is known as a elements it is known as a direct direct combination reactioncombination reaction These These reactions normally release energy reactions normally release energy

A + B A + B AB + energy AB + energy

Synthesis reactions - Synthesis reactions - examplesexamples

MagnesiumMagnesium burns in air ( burns in air (oxygenoxygen) to produce ) to produce magnesium oxidemagnesium oxide (light and heat energy (light and heat energy released)released)

HydrogenHydrogen and and oxygenoxygen combine in an combine in an explosive reaction to produce explosive reaction to produce waterwater (much (much energy released)energy released)

CopperCopper metal combines with yellow metal combines with yellow sulphursulphur when heated to produce when heated to produce copper (I) copper (I) sulphidesulphide (much heat energy is released) (much heat energy is released)

Decomposition and Decomposition and SynthesisSynthesis

Everyday ApplicationsEveryday ApplicationsDecompositionDecomposition

Air bags ndash sodium azide Air bags ndash sodium azide (NaN(NaN33) decomposes to ) decomposes to sodium and nitrogen gas by sodium and nitrogen gas by ignition with a detonating ignition with a detonating capcap

Limestone (primarily CaCOLimestone (primarily CaCO33) ) ndash decomposes to calcium ndash decomposes to calcium oxide and carbon dioxide by oxide and carbon dioxide by heating to make lime (CaO) heating to make lime (CaO) cement and glasscement and glass

Aluminium - the industrial Aluminium - the industrial process of electrolysing process of electrolysing aluminium oxide produces aluminium oxide produces aluminium metalaluminium metal

SynthesisSynthesis Rust ndash iron and oxygen Rust ndash iron and oxygen

combine in the presence of combine in the presence of water to form iron (III) oxidewater to form iron (III) oxide

Burning coke (primarily Burning coke (primarily carbon) is used as a fuel in carbon) is used as a fuel in smelting iron ore in a blast smelting iron ore in a blast furnace during the steel furnace during the steel making process making process

Pollutants - NO (nitric oxide Pollutants - NO (nitric oxide or nitrogen monoxide) and or nitrogen monoxide) and NO2 (nitrogen dioxide) are NO2 (nitrogen dioxide) are formed inside the formed inside the combustion chambers of cars combustion chambers of cars from nitrogen and oxygen from nitrogen and oxygen gasesgases

82 The Chemical Earth82 The Chemical Earth

Focus 5Focus 5

The properties of elements and The properties of elements and compounds are determined by compounds are determined by

their bonding and structuretheir bonding and structure

Properties of elements and Properties of elements and their compounds are very their compounds are very

differentdifferent8Fe(s) + S8Fe(s) + S88(s) + heat (s) + heat 8FeS(s) 8FeS(s)

substancsubstancee

colourcolour Melting Melting point point ((00C)C)

Boiling Boiling point point ((00C)C)

Density Density (gcm(gcm33))

magneticmagnetic

IronIron GreyGrey 15351535 27502750 7979 yesyes

SulphurSulphur YellowYellow 113113 445445 2121 nono

Iron (II) Iron (II) sulphidesulphide

Yellow-Yellow-goldgold

11941194 -- 484484 nono

Properties of elements Properties of elements compounds and mixtures compounds and mixtures

are very differentare very differentAluminiumAluminiumPhysical propertiesPhysical properties MP = 660MP = 66000CC Density = 27 gcmDensity = 27 gcm3 3

Conductivity = 378 x10Conductivity = 378 x1066 Smiddotm-1 Smiddotm-1 (20 degC)(20 degC)

Chemical propertiesChemical properties 4Al(s)+ 3O4Al(s)+ 3O22(g) (g) 2Al 2Al22OO33(s)(s) 2Al(s) + 6HCl(g) 2Al(s) + 6HCl(g) 2AlCl 2AlCl33(aq) (aq)

+ 3H+ 3H22(g)(g)

OxygenOxygenPhysical propertiesPhysical properties MP = -219MP = -21900CC Density = 00013 gcmDensity = 00013 gcm33

Conductivity = non-conductorConductivity = non-conductor

Bauxite ore Bauxite ore (Al(Al22OO33xHxH22O)O)Physical propertiesPhysical properties MP = 2045MP = 204500CC Density = 35-4 gcmDensity = 35-4 gcm33

Conductivity = non-conductorConductivity = non-conductor

Chemical propertiesChemical properties AlAl22OO33(s) + 2NaOH + 3H(s) + 2NaOH + 3H22O(l) O(l)

2Na[Al(OH)2Na[Al(OH)44](aq) (Bayer process)](aq) (Bayer process)

NB Bauxite is essentially an impure NB Bauxite is essentially an impure aluminium oxide The major aluminium oxide The major impurities include iron oxides impurities include iron oxides silicon dioxide and titanium silicon dioxide and titanium dioxide The impurities remain as dioxide The impurities remain as solids and do not react with solids and do not react with NaOH This process removes NaOH This process removes these impuritiesthese impurities

Structure of metalsStructure of metals

Metals can be described as three-Metals can be described as three-dimensional lattices of positive ions in a dimensional lattices of positive ions in a sea of delocalised electrons sea of delocalised electrons

Covalent BondingCovalent Bonding Covalent Molecular-strong Covalent Molecular-strong

bonds weak bonds weak intermolecular forces intermolecular forces holding molecules holding molecules togethertogether

Covalent Network-Covalent Network-covalent bonding lattice covalent bonding lattice that extends indefinitely that extends indefinitely throughout the crystalthroughout the crystal

Ionic bondingIonic bonding

No discreet molecules are formed in No discreet molecules are formed in ionic bonding due to electrostatic ionic bonding due to electrostatic forces holding the atoms together forces holding the atoms together They form a continuing 3D latticeThey form a continuing 3D lattice

-- --

-- -- --

--

-- --

---- --++

++

++

++++

++

++

++++++

Properties associated with Properties associated with bond typesbond types

Metallic bondingMetallic bonding High melting pointsHigh melting points-due to strong attraction between -due to strong attraction between

positively charged metal ions and delocalized positively charged metal ions and delocalized electrons The higher the valency the stronger the electrons The higher the valency the stronger the bond eg Cabond eg Ca2+2+ is stronger than K is stronger than K++

Good conductors of heat and electricityGood conductors of heat and electricity-due to the high -due to the high mobility of delocalized electrons Electrons enter and mobility of delocalized electrons Electrons enter and leave a metal easilyleave a metal easily

Malleable and ductileMalleable and ductile-due to delocalized electrons not -due to delocalized electrons not belonging to any particular metal atom Therefore one belonging to any particular metal atom Therefore one layer of ions can slide over another without disrupting layer of ions can slide over another without disrupting the bond between metal atoms The electrons and the bond between metal atoms The electrons and metal ions simply rearrangemetal ions simply rearrange

HardnessHardness- tend to be hard due to tightly packed atoms- tend to be hard due to tightly packed atoms

Properties associated with Properties associated with bond typesbond types

Ionic bondingIonic bonding High melting pointsHigh melting points-due to strong electrostatic attraction -due to strong electrostatic attraction

between anions and cationsbetween anions and cations

Non-conductors of electricity in solid stateNon-conductors of electricity in solid state-due to -due to oppositely charged particles which are in fixed positionsoppositely charged particles which are in fixed positions

Conductors in the liquid (molten) stateConductors in the liquid (molten) state-due to the ions -due to the ions being able to move freely through the liquidbeing able to move freely through the liquid

HardnessHardness-due to strong electrostatic attraction between -due to strong electrostatic attraction between oppositely charged particlesoppositely charged particles

BrittleBrittle-due to the fixed location of oppositely charged -due to the fixed location of oppositely charged particles Displacement of ions moves them closer to ions particles Displacement of ions moves them closer to ions of a similar charge which increases the repulsive forces of a similar charge which increases the repulsive forces along the fracturealong the fracture

Properties associated with Properties associated with bond typesbond types

Covalent molecular bondingCovalent molecular bonding Low melting pointsLow melting points-due to generally weak -due to generally weak

attractive forces between molecules There attractive forces between molecules There are exceptions to this rule (eg Iare exceptions to this rule (eg I22 melts at melts at 11411400C but decomposes at 1000C but decomposes at 100000C) C)

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

SoftSoft-due to weak forces existing between -due to weak forces existing between moleculesmolecules

Properties associated with Properties associated with bond typesbond types

Covalent Network bondingCovalent Network bonding Very high melting points and boiling Very high melting points and boiling

pointspoints-due to strong covalent bonding -due to strong covalent bonding which form rigid 3-D structureswhich form rigid 3-D structures

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

Extremely hardExtremely hard- due to strong covalent - due to strong covalent bonding which form rigid 3-D structuresbonding which form rigid 3-D structures

The Chemical EarthThe Chemical Earth

Compiled by Robert Slider (2006)

Please share this resource with others

Physical Changes - Physical Changes - examplesexamples

Changing of state (melting iron boiling water)Changing of state (melting iron boiling water) Changing the physical appearance (crushing Changing the physical appearance (crushing

ore in a ball mill drawing copper into wires)ore in a ball mill drawing copper into wires) Dissolving a solid in a liquid (sugar into Dissolving a solid in a liquid (sugar into

water)water) Separation of mixtures (filtering sand from Separation of mixtures (filtering sand from

water separating sea salt from water)water separating sea salt from water)

Physical changes ndash no new substancesPhysical changes ndash no new substances

Chemical Changes - Chemical Changes - indicationsindications

A gas is evolved (iron and HCl generate HA gas is evolved (iron and HCl generate H22 gas) gas) A solid (precipitate) is formed when two A solid (precipitate) is formed when two

solutions are added together (silver nitrate and solutions are added together (silver nitrate and sodium chloride solutions produce a white solid sodium chloride solutions produce a white solid of silver chloride)of silver chloride)

A change in colour (purple potassium A change in colour (purple potassium permanganate (permanganate (KMnO4KMnO4) is added to hydrogen ) is added to hydrogen peroxide the solution turns colourless)peroxide the solution turns colourless)

Change of temperature (magnesium is burned Change of temperature (magnesium is burned in air and becomes very hot)in air and becomes very hot)

Chemical change ndash at least one new Chemical change ndash at least one new substancesubstance

Physical vs Chemical -Physical vs Chemical -WaterWater

Water- a physical Water- a physical changechange

Boiling water is an example Boiling water is an example of relatively weak of relatively weak intermolecular forces intermolecular forces (Hydrogen bonds) (Hydrogen bonds) breakingbreaking

Energy required = 44 kJmolEnergy required = 44 kJmol

Water-a chemical Water-a chemical changechange

Electrolysis of water involves Electrolysis of water involves the breaking of very the breaking of very strong covalent bonds strong covalent bonds between H and O atomsbetween H and O atoms

Energy required = 286 Energy required = 286 kJmolkJmol

Physical vs Chemical -Physical vs Chemical -WaterWater

Boiling ndash breaking H Boiling ndash breaking H bondsbonds

Electrolysis ndash Electrolysis ndash breaking covalent breaking covalent bondsbonds

OOHH

HHHHHH

OOHH

HH

OOHH

HH

OOHH

HH

OOHH

HH

H bondH bond

OO

OO

OOHH

HH

++++

HHHH

Physical vs Chemical -Physical vs Chemical -summarysummary

Chemical changeChemical change

(reaction)(reaction)Physical changePhysical change

At least one new At least one new substance is formedsubstance is formed

No new substances No new substances are formedare formed

Difficult to reverse Difficult to reverse (eg unboiled egg)(eg unboiled egg)

Easily reversed (eg Easily reversed (eg melt ice and freeze it melt ice and freeze it again)again)

Generally requires a Generally requires a large amount of large amount of energyenergy

Generally relatively Generally relatively small quantities of small quantities of energyenergy

Decomposition ReactionsDecomposition Reactions Energy absorbed Energy absorbed

When a compound decomposes into When a compound decomposes into two or more other pure substances two or more other pure substances energy is normally absorbed in the energy is normally absorbed in the form of heat light or electricityform of heat light or electricity

+ AB + AB A + B A + BHeatHeat

LightLight

ElectricityElectricity

Decomposition Reactions-Decomposition Reactions-examplesexamples

HeatHeatSolid Solid copper nitratecopper nitrate decomposes to solid decomposes to solid copper copper

oxideoxide nitrogen dioxidenitrogen dioxide and and oxygenoxygen gases gases

ElectricityElectricityMolten Molten lead bromidelead bromide (400 (40000C) forms C) forms brominebromine gas at gas at

the +ve electrode and liquid the +ve electrode and liquid leadlead at the ndashve at the ndashve electrodeelectrode

LightLightSolid Solid silver chloridesilver chloride decomposes to decomposes to silversilver metal and metal and

chlorinechlorine gas (decomposition of silver compounds gas (decomposition of silver compounds is the basis of photography development)is the basis of photography development)

Synthesis ReactionsSynthesis ReactionsEnergy releasedEnergy released

A synthesis or combination reaction A synthesis or combination reaction involves the combination of two or involves the combination of two or more pure substances When a more pure substances When a compound is formed from its compound is formed from its elements it is known as a elements it is known as a direct direct combination reactioncombination reaction These These reactions normally release energy reactions normally release energy

A + B A + B AB + energy AB + energy

Synthesis reactions - Synthesis reactions - examplesexamples

MagnesiumMagnesium burns in air ( burns in air (oxygenoxygen) to produce ) to produce magnesium oxidemagnesium oxide (light and heat energy (light and heat energy released)released)

HydrogenHydrogen and and oxygenoxygen combine in an combine in an explosive reaction to produce explosive reaction to produce waterwater (much (much energy released)energy released)

CopperCopper metal combines with yellow metal combines with yellow sulphursulphur when heated to produce when heated to produce copper (I) copper (I) sulphidesulphide (much heat energy is released) (much heat energy is released)

Decomposition and Decomposition and SynthesisSynthesis

Everyday ApplicationsEveryday ApplicationsDecompositionDecomposition

Air bags ndash sodium azide Air bags ndash sodium azide (NaN(NaN33) decomposes to ) decomposes to sodium and nitrogen gas by sodium and nitrogen gas by ignition with a detonating ignition with a detonating capcap

Limestone (primarily CaCOLimestone (primarily CaCO33) ) ndash decomposes to calcium ndash decomposes to calcium oxide and carbon dioxide by oxide and carbon dioxide by heating to make lime (CaO) heating to make lime (CaO) cement and glasscement and glass

Aluminium - the industrial Aluminium - the industrial process of electrolysing process of electrolysing aluminium oxide produces aluminium oxide produces aluminium metalaluminium metal

SynthesisSynthesis Rust ndash iron and oxygen Rust ndash iron and oxygen

combine in the presence of combine in the presence of water to form iron (III) oxidewater to form iron (III) oxide

Burning coke (primarily Burning coke (primarily carbon) is used as a fuel in carbon) is used as a fuel in smelting iron ore in a blast smelting iron ore in a blast furnace during the steel furnace during the steel making process making process

Pollutants - NO (nitric oxide Pollutants - NO (nitric oxide or nitrogen monoxide) and or nitrogen monoxide) and NO2 (nitrogen dioxide) are NO2 (nitrogen dioxide) are formed inside the formed inside the combustion chambers of cars combustion chambers of cars from nitrogen and oxygen from nitrogen and oxygen gasesgases

82 The Chemical Earth82 The Chemical Earth

Focus 5Focus 5

The properties of elements and The properties of elements and compounds are determined by compounds are determined by

their bonding and structuretheir bonding and structure

Properties of elements and Properties of elements and their compounds are very their compounds are very

differentdifferent8Fe(s) + S8Fe(s) + S88(s) + heat (s) + heat 8FeS(s) 8FeS(s)

substancsubstancee

colourcolour Melting Melting point point ((00C)C)

Boiling Boiling point point ((00C)C)

Density Density (gcm(gcm33))

magneticmagnetic

IronIron GreyGrey 15351535 27502750 7979 yesyes

SulphurSulphur YellowYellow 113113 445445 2121 nono

Iron (II) Iron (II) sulphidesulphide

Yellow-Yellow-goldgold

11941194 -- 484484 nono

Properties of elements Properties of elements compounds and mixtures compounds and mixtures

are very differentare very differentAluminiumAluminiumPhysical propertiesPhysical properties MP = 660MP = 66000CC Density = 27 gcmDensity = 27 gcm3 3

Conductivity = 378 x10Conductivity = 378 x1066 Smiddotm-1 Smiddotm-1 (20 degC)(20 degC)

Chemical propertiesChemical properties 4Al(s)+ 3O4Al(s)+ 3O22(g) (g) 2Al 2Al22OO33(s)(s) 2Al(s) + 6HCl(g) 2Al(s) + 6HCl(g) 2AlCl 2AlCl33(aq) (aq)

+ 3H+ 3H22(g)(g)

OxygenOxygenPhysical propertiesPhysical properties MP = -219MP = -21900CC Density = 00013 gcmDensity = 00013 gcm33

Conductivity = non-conductorConductivity = non-conductor

Bauxite ore Bauxite ore (Al(Al22OO33xHxH22O)O)Physical propertiesPhysical properties MP = 2045MP = 204500CC Density = 35-4 gcmDensity = 35-4 gcm33

Conductivity = non-conductorConductivity = non-conductor

Chemical propertiesChemical properties AlAl22OO33(s) + 2NaOH + 3H(s) + 2NaOH + 3H22O(l) O(l)

2Na[Al(OH)2Na[Al(OH)44](aq) (Bayer process)](aq) (Bayer process)

NB Bauxite is essentially an impure NB Bauxite is essentially an impure aluminium oxide The major aluminium oxide The major impurities include iron oxides impurities include iron oxides silicon dioxide and titanium silicon dioxide and titanium dioxide The impurities remain as dioxide The impurities remain as solids and do not react with solids and do not react with NaOH This process removes NaOH This process removes these impuritiesthese impurities

Structure of metalsStructure of metals

Metals can be described as three-Metals can be described as three-dimensional lattices of positive ions in a dimensional lattices of positive ions in a sea of delocalised electrons sea of delocalised electrons

Covalent BondingCovalent Bonding Covalent Molecular-strong Covalent Molecular-strong

bonds weak bonds weak intermolecular forces intermolecular forces holding molecules holding molecules togethertogether

Covalent Network-Covalent Network-covalent bonding lattice covalent bonding lattice that extends indefinitely that extends indefinitely throughout the crystalthroughout the crystal

Ionic bondingIonic bonding

No discreet molecules are formed in No discreet molecules are formed in ionic bonding due to electrostatic ionic bonding due to electrostatic forces holding the atoms together forces holding the atoms together They form a continuing 3D latticeThey form a continuing 3D lattice

-- --

-- -- --

--

-- --

---- --++

++

++

++++

++

++

++++++

Properties associated with Properties associated with bond typesbond types

Metallic bondingMetallic bonding High melting pointsHigh melting points-due to strong attraction between -due to strong attraction between

positively charged metal ions and delocalized positively charged metal ions and delocalized electrons The higher the valency the stronger the electrons The higher the valency the stronger the bond eg Cabond eg Ca2+2+ is stronger than K is stronger than K++

Good conductors of heat and electricityGood conductors of heat and electricity-due to the high -due to the high mobility of delocalized electrons Electrons enter and mobility of delocalized electrons Electrons enter and leave a metal easilyleave a metal easily

Malleable and ductileMalleable and ductile-due to delocalized electrons not -due to delocalized electrons not belonging to any particular metal atom Therefore one belonging to any particular metal atom Therefore one layer of ions can slide over another without disrupting layer of ions can slide over another without disrupting the bond between metal atoms The electrons and the bond between metal atoms The electrons and metal ions simply rearrangemetal ions simply rearrange

HardnessHardness- tend to be hard due to tightly packed atoms- tend to be hard due to tightly packed atoms

Properties associated with Properties associated with bond typesbond types

Ionic bondingIonic bonding High melting pointsHigh melting points-due to strong electrostatic attraction -due to strong electrostatic attraction

between anions and cationsbetween anions and cations

Non-conductors of electricity in solid stateNon-conductors of electricity in solid state-due to -due to oppositely charged particles which are in fixed positionsoppositely charged particles which are in fixed positions

Conductors in the liquid (molten) stateConductors in the liquid (molten) state-due to the ions -due to the ions being able to move freely through the liquidbeing able to move freely through the liquid

HardnessHardness-due to strong electrostatic attraction between -due to strong electrostatic attraction between oppositely charged particlesoppositely charged particles

BrittleBrittle-due to the fixed location of oppositely charged -due to the fixed location of oppositely charged particles Displacement of ions moves them closer to ions particles Displacement of ions moves them closer to ions of a similar charge which increases the repulsive forces of a similar charge which increases the repulsive forces along the fracturealong the fracture

Properties associated with Properties associated with bond typesbond types

Covalent molecular bondingCovalent molecular bonding Low melting pointsLow melting points-due to generally weak -due to generally weak

attractive forces between molecules There attractive forces between molecules There are exceptions to this rule (eg Iare exceptions to this rule (eg I22 melts at melts at 11411400C but decomposes at 1000C but decomposes at 100000C) C)

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

SoftSoft-due to weak forces existing between -due to weak forces existing between moleculesmolecules

Properties associated with Properties associated with bond typesbond types

Covalent Network bondingCovalent Network bonding Very high melting points and boiling Very high melting points and boiling

pointspoints-due to strong covalent bonding -due to strong covalent bonding which form rigid 3-D structureswhich form rigid 3-D structures

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

Extremely hardExtremely hard- due to strong covalent - due to strong covalent bonding which form rigid 3-D structuresbonding which form rigid 3-D structures

The Chemical EarthThe Chemical Earth

Compiled by Robert Slider (2006)

Please share this resource with others

Chemical Changes - Chemical Changes - indicationsindications

A gas is evolved (iron and HCl generate HA gas is evolved (iron and HCl generate H22 gas) gas) A solid (precipitate) is formed when two A solid (precipitate) is formed when two

solutions are added together (silver nitrate and solutions are added together (silver nitrate and sodium chloride solutions produce a white solid sodium chloride solutions produce a white solid of silver chloride)of silver chloride)

A change in colour (purple potassium A change in colour (purple potassium permanganate (permanganate (KMnO4KMnO4) is added to hydrogen ) is added to hydrogen peroxide the solution turns colourless)peroxide the solution turns colourless)

Change of temperature (magnesium is burned Change of temperature (magnesium is burned in air and becomes very hot)in air and becomes very hot)

Chemical change ndash at least one new Chemical change ndash at least one new substancesubstance

Physical vs Chemical -Physical vs Chemical -WaterWater

Water- a physical Water- a physical changechange

Boiling water is an example Boiling water is an example of relatively weak of relatively weak intermolecular forces intermolecular forces (Hydrogen bonds) (Hydrogen bonds) breakingbreaking

Energy required = 44 kJmolEnergy required = 44 kJmol

Water-a chemical Water-a chemical changechange

Electrolysis of water involves Electrolysis of water involves the breaking of very the breaking of very strong covalent bonds strong covalent bonds between H and O atomsbetween H and O atoms

Energy required = 286 Energy required = 286 kJmolkJmol

Physical vs Chemical -Physical vs Chemical -WaterWater

Boiling ndash breaking H Boiling ndash breaking H bondsbonds

Electrolysis ndash Electrolysis ndash breaking covalent breaking covalent bondsbonds

OOHH

HHHHHH

OOHH

HH

OOHH

HH

OOHH

HH

OOHH

HH

H bondH bond

OO

OO

OOHH

HH

++++

HHHH

Physical vs Chemical -Physical vs Chemical -summarysummary

Chemical changeChemical change

(reaction)(reaction)Physical changePhysical change

At least one new At least one new substance is formedsubstance is formed

No new substances No new substances are formedare formed

Difficult to reverse Difficult to reverse (eg unboiled egg)(eg unboiled egg)

Easily reversed (eg Easily reversed (eg melt ice and freeze it melt ice and freeze it again)again)

Generally requires a Generally requires a large amount of large amount of energyenergy

Generally relatively Generally relatively small quantities of small quantities of energyenergy

Decomposition ReactionsDecomposition Reactions Energy absorbed Energy absorbed

When a compound decomposes into When a compound decomposes into two or more other pure substances two or more other pure substances energy is normally absorbed in the energy is normally absorbed in the form of heat light or electricityform of heat light or electricity

+ AB + AB A + B A + BHeatHeat

LightLight

ElectricityElectricity

Decomposition Reactions-Decomposition Reactions-examplesexamples

HeatHeatSolid Solid copper nitratecopper nitrate decomposes to solid decomposes to solid copper copper

oxideoxide nitrogen dioxidenitrogen dioxide and and oxygenoxygen gases gases

ElectricityElectricityMolten Molten lead bromidelead bromide (400 (40000C) forms C) forms brominebromine gas at gas at

the +ve electrode and liquid the +ve electrode and liquid leadlead at the ndashve at the ndashve electrodeelectrode

LightLightSolid Solid silver chloridesilver chloride decomposes to decomposes to silversilver metal and metal and

chlorinechlorine gas (decomposition of silver compounds gas (decomposition of silver compounds is the basis of photography development)is the basis of photography development)

Synthesis ReactionsSynthesis ReactionsEnergy releasedEnergy released

A synthesis or combination reaction A synthesis or combination reaction involves the combination of two or involves the combination of two or more pure substances When a more pure substances When a compound is formed from its compound is formed from its elements it is known as a elements it is known as a direct direct combination reactioncombination reaction These These reactions normally release energy reactions normally release energy

A + B A + B AB + energy AB + energy

Synthesis reactions - Synthesis reactions - examplesexamples

MagnesiumMagnesium burns in air ( burns in air (oxygenoxygen) to produce ) to produce magnesium oxidemagnesium oxide (light and heat energy (light and heat energy released)released)

HydrogenHydrogen and and oxygenoxygen combine in an combine in an explosive reaction to produce explosive reaction to produce waterwater (much (much energy released)energy released)

CopperCopper metal combines with yellow metal combines with yellow sulphursulphur when heated to produce when heated to produce copper (I) copper (I) sulphidesulphide (much heat energy is released) (much heat energy is released)

Decomposition and Decomposition and SynthesisSynthesis

Everyday ApplicationsEveryday ApplicationsDecompositionDecomposition

Air bags ndash sodium azide Air bags ndash sodium azide (NaN(NaN33) decomposes to ) decomposes to sodium and nitrogen gas by sodium and nitrogen gas by ignition with a detonating ignition with a detonating capcap

Limestone (primarily CaCOLimestone (primarily CaCO33) ) ndash decomposes to calcium ndash decomposes to calcium oxide and carbon dioxide by oxide and carbon dioxide by heating to make lime (CaO) heating to make lime (CaO) cement and glasscement and glass

Aluminium - the industrial Aluminium - the industrial process of electrolysing process of electrolysing aluminium oxide produces aluminium oxide produces aluminium metalaluminium metal

SynthesisSynthesis Rust ndash iron and oxygen Rust ndash iron and oxygen

combine in the presence of combine in the presence of water to form iron (III) oxidewater to form iron (III) oxide

Burning coke (primarily Burning coke (primarily carbon) is used as a fuel in carbon) is used as a fuel in smelting iron ore in a blast smelting iron ore in a blast furnace during the steel furnace during the steel making process making process

Pollutants - NO (nitric oxide Pollutants - NO (nitric oxide or nitrogen monoxide) and or nitrogen monoxide) and NO2 (nitrogen dioxide) are NO2 (nitrogen dioxide) are formed inside the formed inside the combustion chambers of cars combustion chambers of cars from nitrogen and oxygen from nitrogen and oxygen gasesgases

82 The Chemical Earth82 The Chemical Earth

Focus 5Focus 5

The properties of elements and The properties of elements and compounds are determined by compounds are determined by

their bonding and structuretheir bonding and structure

Properties of elements and Properties of elements and their compounds are very their compounds are very

differentdifferent8Fe(s) + S8Fe(s) + S88(s) + heat (s) + heat 8FeS(s) 8FeS(s)

substancsubstancee

colourcolour Melting Melting point point ((00C)C)

Boiling Boiling point point ((00C)C)

Density Density (gcm(gcm33))

magneticmagnetic

IronIron GreyGrey 15351535 27502750 7979 yesyes

SulphurSulphur YellowYellow 113113 445445 2121 nono

Iron (II) Iron (II) sulphidesulphide

Yellow-Yellow-goldgold

11941194 -- 484484 nono

Properties of elements Properties of elements compounds and mixtures compounds and mixtures

are very differentare very differentAluminiumAluminiumPhysical propertiesPhysical properties MP = 660MP = 66000CC Density = 27 gcmDensity = 27 gcm3 3

Conductivity = 378 x10Conductivity = 378 x1066 Smiddotm-1 Smiddotm-1 (20 degC)(20 degC)

Chemical propertiesChemical properties 4Al(s)+ 3O4Al(s)+ 3O22(g) (g) 2Al 2Al22OO33(s)(s) 2Al(s) + 6HCl(g) 2Al(s) + 6HCl(g) 2AlCl 2AlCl33(aq) (aq)

+ 3H+ 3H22(g)(g)

OxygenOxygenPhysical propertiesPhysical properties MP = -219MP = -21900CC Density = 00013 gcmDensity = 00013 gcm33

Conductivity = non-conductorConductivity = non-conductor

Bauxite ore Bauxite ore (Al(Al22OO33xHxH22O)O)Physical propertiesPhysical properties MP = 2045MP = 204500CC Density = 35-4 gcmDensity = 35-4 gcm33

Conductivity = non-conductorConductivity = non-conductor

Chemical propertiesChemical properties AlAl22OO33(s) + 2NaOH + 3H(s) + 2NaOH + 3H22O(l) O(l)

2Na[Al(OH)2Na[Al(OH)44](aq) (Bayer process)](aq) (Bayer process)

NB Bauxite is essentially an impure NB Bauxite is essentially an impure aluminium oxide The major aluminium oxide The major impurities include iron oxides impurities include iron oxides silicon dioxide and titanium silicon dioxide and titanium dioxide The impurities remain as dioxide The impurities remain as solids and do not react with solids and do not react with NaOH This process removes NaOH This process removes these impuritiesthese impurities

Structure of metalsStructure of metals

Metals can be described as three-Metals can be described as three-dimensional lattices of positive ions in a dimensional lattices of positive ions in a sea of delocalised electrons sea of delocalised electrons

Covalent BondingCovalent Bonding Covalent Molecular-strong Covalent Molecular-strong

bonds weak bonds weak intermolecular forces intermolecular forces holding molecules holding molecules togethertogether

Covalent Network-Covalent Network-covalent bonding lattice covalent bonding lattice that extends indefinitely that extends indefinitely throughout the crystalthroughout the crystal

Ionic bondingIonic bonding

No discreet molecules are formed in No discreet molecules are formed in ionic bonding due to electrostatic ionic bonding due to electrostatic forces holding the atoms together forces holding the atoms together They form a continuing 3D latticeThey form a continuing 3D lattice

-- --

-- -- --

--

-- --

---- --++

++

++

++++

++

++

++++++

Properties associated with Properties associated with bond typesbond types

Metallic bondingMetallic bonding High melting pointsHigh melting points-due to strong attraction between -due to strong attraction between

positively charged metal ions and delocalized positively charged metal ions and delocalized electrons The higher the valency the stronger the electrons The higher the valency the stronger the bond eg Cabond eg Ca2+2+ is stronger than K is stronger than K++

Good conductors of heat and electricityGood conductors of heat and electricity-due to the high -due to the high mobility of delocalized electrons Electrons enter and mobility of delocalized electrons Electrons enter and leave a metal easilyleave a metal easily

Malleable and ductileMalleable and ductile-due to delocalized electrons not -due to delocalized electrons not belonging to any particular metal atom Therefore one belonging to any particular metal atom Therefore one layer of ions can slide over another without disrupting layer of ions can slide over another without disrupting the bond between metal atoms The electrons and the bond between metal atoms The electrons and metal ions simply rearrangemetal ions simply rearrange

HardnessHardness- tend to be hard due to tightly packed atoms- tend to be hard due to tightly packed atoms

Properties associated with Properties associated with bond typesbond types

Ionic bondingIonic bonding High melting pointsHigh melting points-due to strong electrostatic attraction -due to strong electrostatic attraction

between anions and cationsbetween anions and cations

Non-conductors of electricity in solid stateNon-conductors of electricity in solid state-due to -due to oppositely charged particles which are in fixed positionsoppositely charged particles which are in fixed positions

Conductors in the liquid (molten) stateConductors in the liquid (molten) state-due to the ions -due to the ions being able to move freely through the liquidbeing able to move freely through the liquid

HardnessHardness-due to strong electrostatic attraction between -due to strong electrostatic attraction between oppositely charged particlesoppositely charged particles

BrittleBrittle-due to the fixed location of oppositely charged -due to the fixed location of oppositely charged particles Displacement of ions moves them closer to ions particles Displacement of ions moves them closer to ions of a similar charge which increases the repulsive forces of a similar charge which increases the repulsive forces along the fracturealong the fracture

Properties associated with Properties associated with bond typesbond types

Covalent molecular bondingCovalent molecular bonding Low melting pointsLow melting points-due to generally weak -due to generally weak

attractive forces between molecules There attractive forces between molecules There are exceptions to this rule (eg Iare exceptions to this rule (eg I22 melts at melts at 11411400C but decomposes at 1000C but decomposes at 100000C) C)

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

SoftSoft-due to weak forces existing between -due to weak forces existing between moleculesmolecules

Properties associated with Properties associated with bond typesbond types

Covalent Network bondingCovalent Network bonding Very high melting points and boiling Very high melting points and boiling

pointspoints-due to strong covalent bonding -due to strong covalent bonding which form rigid 3-D structureswhich form rigid 3-D structures

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

Extremely hardExtremely hard- due to strong covalent - due to strong covalent bonding which form rigid 3-D structuresbonding which form rigid 3-D structures

The Chemical EarthThe Chemical Earth

Compiled by Robert Slider (2006)

Please share this resource with others

Physical vs Chemical -Physical vs Chemical -WaterWater

Water- a physical Water- a physical changechange

Boiling water is an example Boiling water is an example of relatively weak of relatively weak intermolecular forces intermolecular forces (Hydrogen bonds) (Hydrogen bonds) breakingbreaking

Energy required = 44 kJmolEnergy required = 44 kJmol

Water-a chemical Water-a chemical changechange

Electrolysis of water involves Electrolysis of water involves the breaking of very the breaking of very strong covalent bonds strong covalent bonds between H and O atomsbetween H and O atoms

Energy required = 286 Energy required = 286 kJmolkJmol

Physical vs Chemical -Physical vs Chemical -WaterWater

Boiling ndash breaking H Boiling ndash breaking H bondsbonds

Electrolysis ndash Electrolysis ndash breaking covalent breaking covalent bondsbonds

OOHH

HHHHHH

OOHH

HH

OOHH

HH

OOHH

HH

OOHH

HH

H bondH bond

OO

OO

OOHH

HH

++++

HHHH

Physical vs Chemical -Physical vs Chemical -summarysummary

Chemical changeChemical change

(reaction)(reaction)Physical changePhysical change

At least one new At least one new substance is formedsubstance is formed

No new substances No new substances are formedare formed

Difficult to reverse Difficult to reverse (eg unboiled egg)(eg unboiled egg)

Easily reversed (eg Easily reversed (eg melt ice and freeze it melt ice and freeze it again)again)

Generally requires a Generally requires a large amount of large amount of energyenergy

Generally relatively Generally relatively small quantities of small quantities of energyenergy

Decomposition ReactionsDecomposition Reactions Energy absorbed Energy absorbed

When a compound decomposes into When a compound decomposes into two or more other pure substances two or more other pure substances energy is normally absorbed in the energy is normally absorbed in the form of heat light or electricityform of heat light or electricity

+ AB + AB A + B A + BHeatHeat

LightLight

ElectricityElectricity

Decomposition Reactions-Decomposition Reactions-examplesexamples

HeatHeatSolid Solid copper nitratecopper nitrate decomposes to solid decomposes to solid copper copper

oxideoxide nitrogen dioxidenitrogen dioxide and and oxygenoxygen gases gases

ElectricityElectricityMolten Molten lead bromidelead bromide (400 (40000C) forms C) forms brominebromine gas at gas at

the +ve electrode and liquid the +ve electrode and liquid leadlead at the ndashve at the ndashve electrodeelectrode

LightLightSolid Solid silver chloridesilver chloride decomposes to decomposes to silversilver metal and metal and

chlorinechlorine gas (decomposition of silver compounds gas (decomposition of silver compounds is the basis of photography development)is the basis of photography development)

Synthesis ReactionsSynthesis ReactionsEnergy releasedEnergy released

A synthesis or combination reaction A synthesis or combination reaction involves the combination of two or involves the combination of two or more pure substances When a more pure substances When a compound is formed from its compound is formed from its elements it is known as a elements it is known as a direct direct combination reactioncombination reaction These These reactions normally release energy reactions normally release energy

A + B A + B AB + energy AB + energy

Synthesis reactions - Synthesis reactions - examplesexamples

MagnesiumMagnesium burns in air ( burns in air (oxygenoxygen) to produce ) to produce magnesium oxidemagnesium oxide (light and heat energy (light and heat energy released)released)

HydrogenHydrogen and and oxygenoxygen combine in an combine in an explosive reaction to produce explosive reaction to produce waterwater (much (much energy released)energy released)

CopperCopper metal combines with yellow metal combines with yellow sulphursulphur when heated to produce when heated to produce copper (I) copper (I) sulphidesulphide (much heat energy is released) (much heat energy is released)

Decomposition and Decomposition and SynthesisSynthesis

Everyday ApplicationsEveryday ApplicationsDecompositionDecomposition

Air bags ndash sodium azide Air bags ndash sodium azide (NaN(NaN33) decomposes to ) decomposes to sodium and nitrogen gas by sodium and nitrogen gas by ignition with a detonating ignition with a detonating capcap

Limestone (primarily CaCOLimestone (primarily CaCO33) ) ndash decomposes to calcium ndash decomposes to calcium oxide and carbon dioxide by oxide and carbon dioxide by heating to make lime (CaO) heating to make lime (CaO) cement and glasscement and glass

Aluminium - the industrial Aluminium - the industrial process of electrolysing process of electrolysing aluminium oxide produces aluminium oxide produces aluminium metalaluminium metal

SynthesisSynthesis Rust ndash iron and oxygen Rust ndash iron and oxygen

combine in the presence of combine in the presence of water to form iron (III) oxidewater to form iron (III) oxide

Burning coke (primarily Burning coke (primarily carbon) is used as a fuel in carbon) is used as a fuel in smelting iron ore in a blast smelting iron ore in a blast furnace during the steel furnace during the steel making process making process

Pollutants - NO (nitric oxide Pollutants - NO (nitric oxide or nitrogen monoxide) and or nitrogen monoxide) and NO2 (nitrogen dioxide) are NO2 (nitrogen dioxide) are formed inside the formed inside the combustion chambers of cars combustion chambers of cars from nitrogen and oxygen from nitrogen and oxygen gasesgases

82 The Chemical Earth82 The Chemical Earth

Focus 5Focus 5

The properties of elements and The properties of elements and compounds are determined by compounds are determined by

their bonding and structuretheir bonding and structure

Properties of elements and Properties of elements and their compounds are very their compounds are very

differentdifferent8Fe(s) + S8Fe(s) + S88(s) + heat (s) + heat 8FeS(s) 8FeS(s)

substancsubstancee

colourcolour Melting Melting point point ((00C)C)

Boiling Boiling point point ((00C)C)

Density Density (gcm(gcm33))

magneticmagnetic

IronIron GreyGrey 15351535 27502750 7979 yesyes

SulphurSulphur YellowYellow 113113 445445 2121 nono

Iron (II) Iron (II) sulphidesulphide

Yellow-Yellow-goldgold

11941194 -- 484484 nono

Properties of elements Properties of elements compounds and mixtures compounds and mixtures

are very differentare very differentAluminiumAluminiumPhysical propertiesPhysical properties MP = 660MP = 66000CC Density = 27 gcmDensity = 27 gcm3 3

Conductivity = 378 x10Conductivity = 378 x1066 Smiddotm-1 Smiddotm-1 (20 degC)(20 degC)

Chemical propertiesChemical properties 4Al(s)+ 3O4Al(s)+ 3O22(g) (g) 2Al 2Al22OO33(s)(s) 2Al(s) + 6HCl(g) 2Al(s) + 6HCl(g) 2AlCl 2AlCl33(aq) (aq)

+ 3H+ 3H22(g)(g)

OxygenOxygenPhysical propertiesPhysical properties MP = -219MP = -21900CC Density = 00013 gcmDensity = 00013 gcm33

Conductivity = non-conductorConductivity = non-conductor

Bauxite ore Bauxite ore (Al(Al22OO33xHxH22O)O)Physical propertiesPhysical properties MP = 2045MP = 204500CC Density = 35-4 gcmDensity = 35-4 gcm33

Conductivity = non-conductorConductivity = non-conductor

Chemical propertiesChemical properties AlAl22OO33(s) + 2NaOH + 3H(s) + 2NaOH + 3H22O(l) O(l)

2Na[Al(OH)2Na[Al(OH)44](aq) (Bayer process)](aq) (Bayer process)

NB Bauxite is essentially an impure NB Bauxite is essentially an impure aluminium oxide The major aluminium oxide The major impurities include iron oxides impurities include iron oxides silicon dioxide and titanium silicon dioxide and titanium dioxide The impurities remain as dioxide The impurities remain as solids and do not react with solids and do not react with NaOH This process removes NaOH This process removes these impuritiesthese impurities

Structure of metalsStructure of metals

Metals can be described as three-Metals can be described as three-dimensional lattices of positive ions in a dimensional lattices of positive ions in a sea of delocalised electrons sea of delocalised electrons

Covalent BondingCovalent Bonding Covalent Molecular-strong Covalent Molecular-strong

bonds weak bonds weak intermolecular forces intermolecular forces holding molecules holding molecules togethertogether

Covalent Network-Covalent Network-covalent bonding lattice covalent bonding lattice that extends indefinitely that extends indefinitely throughout the crystalthroughout the crystal

Ionic bondingIonic bonding

No discreet molecules are formed in No discreet molecules are formed in ionic bonding due to electrostatic ionic bonding due to electrostatic forces holding the atoms together forces holding the atoms together They form a continuing 3D latticeThey form a continuing 3D lattice

-- --

-- -- --

--

-- --

---- --++

++

++

++++

++

++

++++++

Properties associated with Properties associated with bond typesbond types

Metallic bondingMetallic bonding High melting pointsHigh melting points-due to strong attraction between -due to strong attraction between

positively charged metal ions and delocalized positively charged metal ions and delocalized electrons The higher the valency the stronger the electrons The higher the valency the stronger the bond eg Cabond eg Ca2+2+ is stronger than K is stronger than K++

Good conductors of heat and electricityGood conductors of heat and electricity-due to the high -due to the high mobility of delocalized electrons Electrons enter and mobility of delocalized electrons Electrons enter and leave a metal easilyleave a metal easily

Malleable and ductileMalleable and ductile-due to delocalized electrons not -due to delocalized electrons not belonging to any particular metal atom Therefore one belonging to any particular metal atom Therefore one layer of ions can slide over another without disrupting layer of ions can slide over another without disrupting the bond between metal atoms The electrons and the bond between metal atoms The electrons and metal ions simply rearrangemetal ions simply rearrange

HardnessHardness- tend to be hard due to tightly packed atoms- tend to be hard due to tightly packed atoms

Properties associated with Properties associated with bond typesbond types

Ionic bondingIonic bonding High melting pointsHigh melting points-due to strong electrostatic attraction -due to strong electrostatic attraction

between anions and cationsbetween anions and cations

Non-conductors of electricity in solid stateNon-conductors of electricity in solid state-due to -due to oppositely charged particles which are in fixed positionsoppositely charged particles which are in fixed positions

Conductors in the liquid (molten) stateConductors in the liquid (molten) state-due to the ions -due to the ions being able to move freely through the liquidbeing able to move freely through the liquid

HardnessHardness-due to strong electrostatic attraction between -due to strong electrostatic attraction between oppositely charged particlesoppositely charged particles

BrittleBrittle-due to the fixed location of oppositely charged -due to the fixed location of oppositely charged particles Displacement of ions moves them closer to ions particles Displacement of ions moves them closer to ions of a similar charge which increases the repulsive forces of a similar charge which increases the repulsive forces along the fracturealong the fracture

Properties associated with Properties associated with bond typesbond types

Covalent molecular bondingCovalent molecular bonding Low melting pointsLow melting points-due to generally weak -due to generally weak

attractive forces between molecules There attractive forces between molecules There are exceptions to this rule (eg Iare exceptions to this rule (eg I22 melts at melts at 11411400C but decomposes at 1000C but decomposes at 100000C) C)

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

SoftSoft-due to weak forces existing between -due to weak forces existing between moleculesmolecules

Properties associated with Properties associated with bond typesbond types

Covalent Network bondingCovalent Network bonding Very high melting points and boiling Very high melting points and boiling

pointspoints-due to strong covalent bonding -due to strong covalent bonding which form rigid 3-D structureswhich form rigid 3-D structures

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

Extremely hardExtremely hard- due to strong covalent - due to strong covalent bonding which form rigid 3-D structuresbonding which form rigid 3-D structures

The Chemical EarthThe Chemical Earth

Compiled by Robert Slider (2006)

Please share this resource with others

Physical vs Chemical -Physical vs Chemical -WaterWater

Boiling ndash breaking H Boiling ndash breaking H bondsbonds

Electrolysis ndash Electrolysis ndash breaking covalent breaking covalent bondsbonds

OOHH

HHHHHH

OOHH

HH

OOHH

HH

OOHH

HH

OOHH

HH

H bondH bond

OO

OO

OOHH

HH

++++

HHHH

Physical vs Chemical -Physical vs Chemical -summarysummary

Chemical changeChemical change

(reaction)(reaction)Physical changePhysical change

At least one new At least one new substance is formedsubstance is formed

No new substances No new substances are formedare formed

Difficult to reverse Difficult to reverse (eg unboiled egg)(eg unboiled egg)

Easily reversed (eg Easily reversed (eg melt ice and freeze it melt ice and freeze it again)again)

Generally requires a Generally requires a large amount of large amount of energyenergy

Generally relatively Generally relatively small quantities of small quantities of energyenergy

Decomposition ReactionsDecomposition Reactions Energy absorbed Energy absorbed

When a compound decomposes into When a compound decomposes into two or more other pure substances two or more other pure substances energy is normally absorbed in the energy is normally absorbed in the form of heat light or electricityform of heat light or electricity

+ AB + AB A + B A + BHeatHeat

LightLight

ElectricityElectricity

Decomposition Reactions-Decomposition Reactions-examplesexamples

HeatHeatSolid Solid copper nitratecopper nitrate decomposes to solid decomposes to solid copper copper

oxideoxide nitrogen dioxidenitrogen dioxide and and oxygenoxygen gases gases

ElectricityElectricityMolten Molten lead bromidelead bromide (400 (40000C) forms C) forms brominebromine gas at gas at

the +ve electrode and liquid the +ve electrode and liquid leadlead at the ndashve at the ndashve electrodeelectrode

LightLightSolid Solid silver chloridesilver chloride decomposes to decomposes to silversilver metal and metal and

chlorinechlorine gas (decomposition of silver compounds gas (decomposition of silver compounds is the basis of photography development)is the basis of photography development)

Synthesis ReactionsSynthesis ReactionsEnergy releasedEnergy released

A synthesis or combination reaction A synthesis or combination reaction involves the combination of two or involves the combination of two or more pure substances When a more pure substances When a compound is formed from its compound is formed from its elements it is known as a elements it is known as a direct direct combination reactioncombination reaction These These reactions normally release energy reactions normally release energy

A + B A + B AB + energy AB + energy

Synthesis reactions - Synthesis reactions - examplesexamples

MagnesiumMagnesium burns in air ( burns in air (oxygenoxygen) to produce ) to produce magnesium oxidemagnesium oxide (light and heat energy (light and heat energy released)released)

HydrogenHydrogen and and oxygenoxygen combine in an combine in an explosive reaction to produce explosive reaction to produce waterwater (much (much energy released)energy released)

CopperCopper metal combines with yellow metal combines with yellow sulphursulphur when heated to produce when heated to produce copper (I) copper (I) sulphidesulphide (much heat energy is released) (much heat energy is released)

Decomposition and Decomposition and SynthesisSynthesis

Everyday ApplicationsEveryday ApplicationsDecompositionDecomposition

Air bags ndash sodium azide Air bags ndash sodium azide (NaN(NaN33) decomposes to ) decomposes to sodium and nitrogen gas by sodium and nitrogen gas by ignition with a detonating ignition with a detonating capcap

Limestone (primarily CaCOLimestone (primarily CaCO33) ) ndash decomposes to calcium ndash decomposes to calcium oxide and carbon dioxide by oxide and carbon dioxide by heating to make lime (CaO) heating to make lime (CaO) cement and glasscement and glass

Aluminium - the industrial Aluminium - the industrial process of electrolysing process of electrolysing aluminium oxide produces aluminium oxide produces aluminium metalaluminium metal

SynthesisSynthesis Rust ndash iron and oxygen Rust ndash iron and oxygen

combine in the presence of combine in the presence of water to form iron (III) oxidewater to form iron (III) oxide

Burning coke (primarily Burning coke (primarily carbon) is used as a fuel in carbon) is used as a fuel in smelting iron ore in a blast smelting iron ore in a blast furnace during the steel furnace during the steel making process making process

Pollutants - NO (nitric oxide Pollutants - NO (nitric oxide or nitrogen monoxide) and or nitrogen monoxide) and NO2 (nitrogen dioxide) are NO2 (nitrogen dioxide) are formed inside the formed inside the combustion chambers of cars combustion chambers of cars from nitrogen and oxygen from nitrogen and oxygen gasesgases

82 The Chemical Earth82 The Chemical Earth

Focus 5Focus 5

The properties of elements and The properties of elements and compounds are determined by compounds are determined by

their bonding and structuretheir bonding and structure

Properties of elements and Properties of elements and their compounds are very their compounds are very

differentdifferent8Fe(s) + S8Fe(s) + S88(s) + heat (s) + heat 8FeS(s) 8FeS(s)

substancsubstancee

colourcolour Melting Melting point point ((00C)C)

Boiling Boiling point point ((00C)C)

Density Density (gcm(gcm33))

magneticmagnetic

IronIron GreyGrey 15351535 27502750 7979 yesyes

SulphurSulphur YellowYellow 113113 445445 2121 nono

Iron (II) Iron (II) sulphidesulphide

Yellow-Yellow-goldgold

11941194 -- 484484 nono

Properties of elements Properties of elements compounds and mixtures compounds and mixtures

are very differentare very differentAluminiumAluminiumPhysical propertiesPhysical properties MP = 660MP = 66000CC Density = 27 gcmDensity = 27 gcm3 3

Conductivity = 378 x10Conductivity = 378 x1066 Smiddotm-1 Smiddotm-1 (20 degC)(20 degC)

Chemical propertiesChemical properties 4Al(s)+ 3O4Al(s)+ 3O22(g) (g) 2Al 2Al22OO33(s)(s) 2Al(s) + 6HCl(g) 2Al(s) + 6HCl(g) 2AlCl 2AlCl33(aq) (aq)

+ 3H+ 3H22(g)(g)

OxygenOxygenPhysical propertiesPhysical properties MP = -219MP = -21900CC Density = 00013 gcmDensity = 00013 gcm33

Conductivity = non-conductorConductivity = non-conductor

Bauxite ore Bauxite ore (Al(Al22OO33xHxH22O)O)Physical propertiesPhysical properties MP = 2045MP = 204500CC Density = 35-4 gcmDensity = 35-4 gcm33

Conductivity = non-conductorConductivity = non-conductor

Chemical propertiesChemical properties AlAl22OO33(s) + 2NaOH + 3H(s) + 2NaOH + 3H22O(l) O(l)

2Na[Al(OH)2Na[Al(OH)44](aq) (Bayer process)](aq) (Bayer process)

NB Bauxite is essentially an impure NB Bauxite is essentially an impure aluminium oxide The major aluminium oxide The major impurities include iron oxides impurities include iron oxides silicon dioxide and titanium silicon dioxide and titanium dioxide The impurities remain as dioxide The impurities remain as solids and do not react with solids and do not react with NaOH This process removes NaOH This process removes these impuritiesthese impurities

Structure of metalsStructure of metals

Metals can be described as three-Metals can be described as three-dimensional lattices of positive ions in a dimensional lattices of positive ions in a sea of delocalised electrons sea of delocalised electrons

Covalent BondingCovalent Bonding Covalent Molecular-strong Covalent Molecular-strong

bonds weak bonds weak intermolecular forces intermolecular forces holding molecules holding molecules togethertogether

Covalent Network-Covalent Network-covalent bonding lattice covalent bonding lattice that extends indefinitely that extends indefinitely throughout the crystalthroughout the crystal

Ionic bondingIonic bonding

No discreet molecules are formed in No discreet molecules are formed in ionic bonding due to electrostatic ionic bonding due to electrostatic forces holding the atoms together forces holding the atoms together They form a continuing 3D latticeThey form a continuing 3D lattice

-- --

-- -- --

--

-- --

---- --++

++

++

++++

++

++

++++++

Properties associated with Properties associated with bond typesbond types

Metallic bondingMetallic bonding High melting pointsHigh melting points-due to strong attraction between -due to strong attraction between

positively charged metal ions and delocalized positively charged metal ions and delocalized electrons The higher the valency the stronger the electrons The higher the valency the stronger the bond eg Cabond eg Ca2+2+ is stronger than K is stronger than K++

Good conductors of heat and electricityGood conductors of heat and electricity-due to the high -due to the high mobility of delocalized electrons Electrons enter and mobility of delocalized electrons Electrons enter and leave a metal easilyleave a metal easily

Malleable and ductileMalleable and ductile-due to delocalized electrons not -due to delocalized electrons not belonging to any particular metal atom Therefore one belonging to any particular metal atom Therefore one layer of ions can slide over another without disrupting layer of ions can slide over another without disrupting the bond between metal atoms The electrons and the bond between metal atoms The electrons and metal ions simply rearrangemetal ions simply rearrange

HardnessHardness- tend to be hard due to tightly packed atoms- tend to be hard due to tightly packed atoms

Properties associated with Properties associated with bond typesbond types

Ionic bondingIonic bonding High melting pointsHigh melting points-due to strong electrostatic attraction -due to strong electrostatic attraction

between anions and cationsbetween anions and cations

Non-conductors of electricity in solid stateNon-conductors of electricity in solid state-due to -due to oppositely charged particles which are in fixed positionsoppositely charged particles which are in fixed positions

Conductors in the liquid (molten) stateConductors in the liquid (molten) state-due to the ions -due to the ions being able to move freely through the liquidbeing able to move freely through the liquid

HardnessHardness-due to strong electrostatic attraction between -due to strong electrostatic attraction between oppositely charged particlesoppositely charged particles

BrittleBrittle-due to the fixed location of oppositely charged -due to the fixed location of oppositely charged particles Displacement of ions moves them closer to ions particles Displacement of ions moves them closer to ions of a similar charge which increases the repulsive forces of a similar charge which increases the repulsive forces along the fracturealong the fracture

Properties associated with Properties associated with bond typesbond types

Covalent molecular bondingCovalent molecular bonding Low melting pointsLow melting points-due to generally weak -due to generally weak

attractive forces between molecules There attractive forces between molecules There are exceptions to this rule (eg Iare exceptions to this rule (eg I22 melts at melts at 11411400C but decomposes at 1000C but decomposes at 100000C) C)

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

SoftSoft-due to weak forces existing between -due to weak forces existing between moleculesmolecules

Properties associated with Properties associated with bond typesbond types

Covalent Network bondingCovalent Network bonding Very high melting points and boiling Very high melting points and boiling

pointspoints-due to strong covalent bonding -due to strong covalent bonding which form rigid 3-D structureswhich form rigid 3-D structures

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

Extremely hardExtremely hard- due to strong covalent - due to strong covalent bonding which form rigid 3-D structuresbonding which form rigid 3-D structures

The Chemical EarthThe Chemical Earth

Compiled by Robert Slider (2006)

Please share this resource with others

Physical vs Chemical -Physical vs Chemical -summarysummary

Chemical changeChemical change

(reaction)(reaction)Physical changePhysical change

At least one new At least one new substance is formedsubstance is formed

No new substances No new substances are formedare formed

Difficult to reverse Difficult to reverse (eg unboiled egg)(eg unboiled egg)

Easily reversed (eg Easily reversed (eg melt ice and freeze it melt ice and freeze it again)again)

Generally requires a Generally requires a large amount of large amount of energyenergy

Generally relatively Generally relatively small quantities of small quantities of energyenergy

Decomposition ReactionsDecomposition Reactions Energy absorbed Energy absorbed

When a compound decomposes into When a compound decomposes into two or more other pure substances two or more other pure substances energy is normally absorbed in the energy is normally absorbed in the form of heat light or electricityform of heat light or electricity

+ AB + AB A + B A + BHeatHeat

LightLight

ElectricityElectricity

Decomposition Reactions-Decomposition Reactions-examplesexamples

HeatHeatSolid Solid copper nitratecopper nitrate decomposes to solid decomposes to solid copper copper

oxideoxide nitrogen dioxidenitrogen dioxide and and oxygenoxygen gases gases

ElectricityElectricityMolten Molten lead bromidelead bromide (400 (40000C) forms C) forms brominebromine gas at gas at

the +ve electrode and liquid the +ve electrode and liquid leadlead at the ndashve at the ndashve electrodeelectrode

LightLightSolid Solid silver chloridesilver chloride decomposes to decomposes to silversilver metal and metal and

chlorinechlorine gas (decomposition of silver compounds gas (decomposition of silver compounds is the basis of photography development)is the basis of photography development)

Synthesis ReactionsSynthesis ReactionsEnergy releasedEnergy released

A synthesis or combination reaction A synthesis or combination reaction involves the combination of two or involves the combination of two or more pure substances When a more pure substances When a compound is formed from its compound is formed from its elements it is known as a elements it is known as a direct direct combination reactioncombination reaction These These reactions normally release energy reactions normally release energy

A + B A + B AB + energy AB + energy

Synthesis reactions - Synthesis reactions - examplesexamples

MagnesiumMagnesium burns in air ( burns in air (oxygenoxygen) to produce ) to produce magnesium oxidemagnesium oxide (light and heat energy (light and heat energy released)released)

HydrogenHydrogen and and oxygenoxygen combine in an combine in an explosive reaction to produce explosive reaction to produce waterwater (much (much energy released)energy released)

CopperCopper metal combines with yellow metal combines with yellow sulphursulphur when heated to produce when heated to produce copper (I) copper (I) sulphidesulphide (much heat energy is released) (much heat energy is released)

Decomposition and Decomposition and SynthesisSynthesis

Everyday ApplicationsEveryday ApplicationsDecompositionDecomposition

Air bags ndash sodium azide Air bags ndash sodium azide (NaN(NaN33) decomposes to ) decomposes to sodium and nitrogen gas by sodium and nitrogen gas by ignition with a detonating ignition with a detonating capcap

Limestone (primarily CaCOLimestone (primarily CaCO33) ) ndash decomposes to calcium ndash decomposes to calcium oxide and carbon dioxide by oxide and carbon dioxide by heating to make lime (CaO) heating to make lime (CaO) cement and glasscement and glass

Aluminium - the industrial Aluminium - the industrial process of electrolysing process of electrolysing aluminium oxide produces aluminium oxide produces aluminium metalaluminium metal

SynthesisSynthesis Rust ndash iron and oxygen Rust ndash iron and oxygen

combine in the presence of combine in the presence of water to form iron (III) oxidewater to form iron (III) oxide

Burning coke (primarily Burning coke (primarily carbon) is used as a fuel in carbon) is used as a fuel in smelting iron ore in a blast smelting iron ore in a blast furnace during the steel furnace during the steel making process making process

Pollutants - NO (nitric oxide Pollutants - NO (nitric oxide or nitrogen monoxide) and or nitrogen monoxide) and NO2 (nitrogen dioxide) are NO2 (nitrogen dioxide) are formed inside the formed inside the combustion chambers of cars combustion chambers of cars from nitrogen and oxygen from nitrogen and oxygen gasesgases

82 The Chemical Earth82 The Chemical Earth

Focus 5Focus 5

The properties of elements and The properties of elements and compounds are determined by compounds are determined by

their bonding and structuretheir bonding and structure

Properties of elements and Properties of elements and their compounds are very their compounds are very

differentdifferent8Fe(s) + S8Fe(s) + S88(s) + heat (s) + heat 8FeS(s) 8FeS(s)

substancsubstancee

colourcolour Melting Melting point point ((00C)C)

Boiling Boiling point point ((00C)C)

Density Density (gcm(gcm33))

magneticmagnetic

IronIron GreyGrey 15351535 27502750 7979 yesyes

SulphurSulphur YellowYellow 113113 445445 2121 nono

Iron (II) Iron (II) sulphidesulphide

Yellow-Yellow-goldgold

11941194 -- 484484 nono

Properties of elements Properties of elements compounds and mixtures compounds and mixtures

are very differentare very differentAluminiumAluminiumPhysical propertiesPhysical properties MP = 660MP = 66000CC Density = 27 gcmDensity = 27 gcm3 3

Conductivity = 378 x10Conductivity = 378 x1066 Smiddotm-1 Smiddotm-1 (20 degC)(20 degC)

Chemical propertiesChemical properties 4Al(s)+ 3O4Al(s)+ 3O22(g) (g) 2Al 2Al22OO33(s)(s) 2Al(s) + 6HCl(g) 2Al(s) + 6HCl(g) 2AlCl 2AlCl33(aq) (aq)

+ 3H+ 3H22(g)(g)

OxygenOxygenPhysical propertiesPhysical properties MP = -219MP = -21900CC Density = 00013 gcmDensity = 00013 gcm33

Conductivity = non-conductorConductivity = non-conductor

Bauxite ore Bauxite ore (Al(Al22OO33xHxH22O)O)Physical propertiesPhysical properties MP = 2045MP = 204500CC Density = 35-4 gcmDensity = 35-4 gcm33

Conductivity = non-conductorConductivity = non-conductor

Chemical propertiesChemical properties AlAl22OO33(s) + 2NaOH + 3H(s) + 2NaOH + 3H22O(l) O(l)

2Na[Al(OH)2Na[Al(OH)44](aq) (Bayer process)](aq) (Bayer process)

NB Bauxite is essentially an impure NB Bauxite is essentially an impure aluminium oxide The major aluminium oxide The major impurities include iron oxides impurities include iron oxides silicon dioxide and titanium silicon dioxide and titanium dioxide The impurities remain as dioxide The impurities remain as solids and do not react with solids and do not react with NaOH This process removes NaOH This process removes these impuritiesthese impurities

Structure of metalsStructure of metals

Metals can be described as three-Metals can be described as three-dimensional lattices of positive ions in a dimensional lattices of positive ions in a sea of delocalised electrons sea of delocalised electrons

Covalent BondingCovalent Bonding Covalent Molecular-strong Covalent Molecular-strong

bonds weak bonds weak intermolecular forces intermolecular forces holding molecules holding molecules togethertogether

Covalent Network-Covalent Network-covalent bonding lattice covalent bonding lattice that extends indefinitely that extends indefinitely throughout the crystalthroughout the crystal

Ionic bondingIonic bonding

No discreet molecules are formed in No discreet molecules are formed in ionic bonding due to electrostatic ionic bonding due to electrostatic forces holding the atoms together forces holding the atoms together They form a continuing 3D latticeThey form a continuing 3D lattice

-- --

-- -- --

--

-- --

---- --++

++

++

++++

++

++

++++++

Properties associated with Properties associated with bond typesbond types

Metallic bondingMetallic bonding High melting pointsHigh melting points-due to strong attraction between -due to strong attraction between

positively charged metal ions and delocalized positively charged metal ions and delocalized electrons The higher the valency the stronger the electrons The higher the valency the stronger the bond eg Cabond eg Ca2+2+ is stronger than K is stronger than K++

Good conductors of heat and electricityGood conductors of heat and electricity-due to the high -due to the high mobility of delocalized electrons Electrons enter and mobility of delocalized electrons Electrons enter and leave a metal easilyleave a metal easily

Malleable and ductileMalleable and ductile-due to delocalized electrons not -due to delocalized electrons not belonging to any particular metal atom Therefore one belonging to any particular metal atom Therefore one layer of ions can slide over another without disrupting layer of ions can slide over another without disrupting the bond between metal atoms The electrons and the bond between metal atoms The electrons and metal ions simply rearrangemetal ions simply rearrange

HardnessHardness- tend to be hard due to tightly packed atoms- tend to be hard due to tightly packed atoms

Properties associated with Properties associated with bond typesbond types

Ionic bondingIonic bonding High melting pointsHigh melting points-due to strong electrostatic attraction -due to strong electrostatic attraction

between anions and cationsbetween anions and cations

Non-conductors of electricity in solid stateNon-conductors of electricity in solid state-due to -due to oppositely charged particles which are in fixed positionsoppositely charged particles which are in fixed positions

Conductors in the liquid (molten) stateConductors in the liquid (molten) state-due to the ions -due to the ions being able to move freely through the liquidbeing able to move freely through the liquid

HardnessHardness-due to strong electrostatic attraction between -due to strong electrostatic attraction between oppositely charged particlesoppositely charged particles

BrittleBrittle-due to the fixed location of oppositely charged -due to the fixed location of oppositely charged particles Displacement of ions moves them closer to ions particles Displacement of ions moves them closer to ions of a similar charge which increases the repulsive forces of a similar charge which increases the repulsive forces along the fracturealong the fracture

Properties associated with Properties associated with bond typesbond types

Covalent molecular bondingCovalent molecular bonding Low melting pointsLow melting points-due to generally weak -due to generally weak

attractive forces between molecules There attractive forces between molecules There are exceptions to this rule (eg Iare exceptions to this rule (eg I22 melts at melts at 11411400C but decomposes at 1000C but decomposes at 100000C) C)

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

SoftSoft-due to weak forces existing between -due to weak forces existing between moleculesmolecules

Properties associated with Properties associated with bond typesbond types

Covalent Network bondingCovalent Network bonding Very high melting points and boiling Very high melting points and boiling

pointspoints-due to strong covalent bonding -due to strong covalent bonding which form rigid 3-D structureswhich form rigid 3-D structures

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

Extremely hardExtremely hard- due to strong covalent - due to strong covalent bonding which form rigid 3-D structuresbonding which form rigid 3-D structures

The Chemical EarthThe Chemical Earth

Compiled by Robert Slider (2006)

Please share this resource with others

Decomposition ReactionsDecomposition Reactions Energy absorbed Energy absorbed

When a compound decomposes into When a compound decomposes into two or more other pure substances two or more other pure substances energy is normally absorbed in the energy is normally absorbed in the form of heat light or electricityform of heat light or electricity

+ AB + AB A + B A + BHeatHeat

LightLight

ElectricityElectricity

Decomposition Reactions-Decomposition Reactions-examplesexamples

HeatHeatSolid Solid copper nitratecopper nitrate decomposes to solid decomposes to solid copper copper

oxideoxide nitrogen dioxidenitrogen dioxide and and oxygenoxygen gases gases

ElectricityElectricityMolten Molten lead bromidelead bromide (400 (40000C) forms C) forms brominebromine gas at gas at

the +ve electrode and liquid the +ve electrode and liquid leadlead at the ndashve at the ndashve electrodeelectrode

LightLightSolid Solid silver chloridesilver chloride decomposes to decomposes to silversilver metal and metal and

chlorinechlorine gas (decomposition of silver compounds gas (decomposition of silver compounds is the basis of photography development)is the basis of photography development)

Synthesis ReactionsSynthesis ReactionsEnergy releasedEnergy released

A synthesis or combination reaction A synthesis or combination reaction involves the combination of two or involves the combination of two or more pure substances When a more pure substances When a compound is formed from its compound is formed from its elements it is known as a elements it is known as a direct direct combination reactioncombination reaction These These reactions normally release energy reactions normally release energy

A + B A + B AB + energy AB + energy

Synthesis reactions - Synthesis reactions - examplesexamples

MagnesiumMagnesium burns in air ( burns in air (oxygenoxygen) to produce ) to produce magnesium oxidemagnesium oxide (light and heat energy (light and heat energy released)released)

HydrogenHydrogen and and oxygenoxygen combine in an combine in an explosive reaction to produce explosive reaction to produce waterwater (much (much energy released)energy released)

CopperCopper metal combines with yellow metal combines with yellow sulphursulphur when heated to produce when heated to produce copper (I) copper (I) sulphidesulphide (much heat energy is released) (much heat energy is released)

Decomposition and Decomposition and SynthesisSynthesis

Everyday ApplicationsEveryday ApplicationsDecompositionDecomposition

Air bags ndash sodium azide Air bags ndash sodium azide (NaN(NaN33) decomposes to ) decomposes to sodium and nitrogen gas by sodium and nitrogen gas by ignition with a detonating ignition with a detonating capcap

Limestone (primarily CaCOLimestone (primarily CaCO33) ) ndash decomposes to calcium ndash decomposes to calcium oxide and carbon dioxide by oxide and carbon dioxide by heating to make lime (CaO) heating to make lime (CaO) cement and glasscement and glass

Aluminium - the industrial Aluminium - the industrial process of electrolysing process of electrolysing aluminium oxide produces aluminium oxide produces aluminium metalaluminium metal

SynthesisSynthesis Rust ndash iron and oxygen Rust ndash iron and oxygen

combine in the presence of combine in the presence of water to form iron (III) oxidewater to form iron (III) oxide

Burning coke (primarily Burning coke (primarily carbon) is used as a fuel in carbon) is used as a fuel in smelting iron ore in a blast smelting iron ore in a blast furnace during the steel furnace during the steel making process making process

Pollutants - NO (nitric oxide Pollutants - NO (nitric oxide or nitrogen monoxide) and or nitrogen monoxide) and NO2 (nitrogen dioxide) are NO2 (nitrogen dioxide) are formed inside the formed inside the combustion chambers of cars combustion chambers of cars from nitrogen and oxygen from nitrogen and oxygen gasesgases

82 The Chemical Earth82 The Chemical Earth

Focus 5Focus 5

The properties of elements and The properties of elements and compounds are determined by compounds are determined by

their bonding and structuretheir bonding and structure

Properties of elements and Properties of elements and their compounds are very their compounds are very

differentdifferent8Fe(s) + S8Fe(s) + S88(s) + heat (s) + heat 8FeS(s) 8FeS(s)

substancsubstancee

colourcolour Melting Melting point point ((00C)C)

Boiling Boiling point point ((00C)C)

Density Density (gcm(gcm33))

magneticmagnetic

IronIron GreyGrey 15351535 27502750 7979 yesyes

SulphurSulphur YellowYellow 113113 445445 2121 nono

Iron (II) Iron (II) sulphidesulphide

Yellow-Yellow-goldgold

11941194 -- 484484 nono

Properties of elements Properties of elements compounds and mixtures compounds and mixtures

are very differentare very differentAluminiumAluminiumPhysical propertiesPhysical properties MP = 660MP = 66000CC Density = 27 gcmDensity = 27 gcm3 3

Conductivity = 378 x10Conductivity = 378 x1066 Smiddotm-1 Smiddotm-1 (20 degC)(20 degC)

Chemical propertiesChemical properties 4Al(s)+ 3O4Al(s)+ 3O22(g) (g) 2Al 2Al22OO33(s)(s) 2Al(s) + 6HCl(g) 2Al(s) + 6HCl(g) 2AlCl 2AlCl33(aq) (aq)

+ 3H+ 3H22(g)(g)

OxygenOxygenPhysical propertiesPhysical properties MP = -219MP = -21900CC Density = 00013 gcmDensity = 00013 gcm33

Conductivity = non-conductorConductivity = non-conductor

Bauxite ore Bauxite ore (Al(Al22OO33xHxH22O)O)Physical propertiesPhysical properties MP = 2045MP = 204500CC Density = 35-4 gcmDensity = 35-4 gcm33

Conductivity = non-conductorConductivity = non-conductor

Chemical propertiesChemical properties AlAl22OO33(s) + 2NaOH + 3H(s) + 2NaOH + 3H22O(l) O(l)

2Na[Al(OH)2Na[Al(OH)44](aq) (Bayer process)](aq) (Bayer process)

NB Bauxite is essentially an impure NB Bauxite is essentially an impure aluminium oxide The major aluminium oxide The major impurities include iron oxides impurities include iron oxides silicon dioxide and titanium silicon dioxide and titanium dioxide The impurities remain as dioxide The impurities remain as solids and do not react with solids and do not react with NaOH This process removes NaOH This process removes these impuritiesthese impurities

Structure of metalsStructure of metals

Metals can be described as three-Metals can be described as three-dimensional lattices of positive ions in a dimensional lattices of positive ions in a sea of delocalised electrons sea of delocalised electrons

Covalent BondingCovalent Bonding Covalent Molecular-strong Covalent Molecular-strong

bonds weak bonds weak intermolecular forces intermolecular forces holding molecules holding molecules togethertogether

Covalent Network-Covalent Network-covalent bonding lattice covalent bonding lattice that extends indefinitely that extends indefinitely throughout the crystalthroughout the crystal

Ionic bondingIonic bonding

No discreet molecules are formed in No discreet molecules are formed in ionic bonding due to electrostatic ionic bonding due to electrostatic forces holding the atoms together forces holding the atoms together They form a continuing 3D latticeThey form a continuing 3D lattice

-- --

-- -- --

--

-- --

---- --++

++

++

++++

++

++

++++++

Properties associated with Properties associated with bond typesbond types

Metallic bondingMetallic bonding High melting pointsHigh melting points-due to strong attraction between -due to strong attraction between

positively charged metal ions and delocalized positively charged metal ions and delocalized electrons The higher the valency the stronger the electrons The higher the valency the stronger the bond eg Cabond eg Ca2+2+ is stronger than K is stronger than K++

Good conductors of heat and electricityGood conductors of heat and electricity-due to the high -due to the high mobility of delocalized electrons Electrons enter and mobility of delocalized electrons Electrons enter and leave a metal easilyleave a metal easily

Malleable and ductileMalleable and ductile-due to delocalized electrons not -due to delocalized electrons not belonging to any particular metal atom Therefore one belonging to any particular metal atom Therefore one layer of ions can slide over another without disrupting layer of ions can slide over another without disrupting the bond between metal atoms The electrons and the bond between metal atoms The electrons and metal ions simply rearrangemetal ions simply rearrange

HardnessHardness- tend to be hard due to tightly packed atoms- tend to be hard due to tightly packed atoms

Properties associated with Properties associated with bond typesbond types

Ionic bondingIonic bonding High melting pointsHigh melting points-due to strong electrostatic attraction -due to strong electrostatic attraction

between anions and cationsbetween anions and cations

Non-conductors of electricity in solid stateNon-conductors of electricity in solid state-due to -due to oppositely charged particles which are in fixed positionsoppositely charged particles which are in fixed positions

Conductors in the liquid (molten) stateConductors in the liquid (molten) state-due to the ions -due to the ions being able to move freely through the liquidbeing able to move freely through the liquid

HardnessHardness-due to strong electrostatic attraction between -due to strong electrostatic attraction between oppositely charged particlesoppositely charged particles

BrittleBrittle-due to the fixed location of oppositely charged -due to the fixed location of oppositely charged particles Displacement of ions moves them closer to ions particles Displacement of ions moves them closer to ions of a similar charge which increases the repulsive forces of a similar charge which increases the repulsive forces along the fracturealong the fracture

Properties associated with Properties associated with bond typesbond types

Covalent molecular bondingCovalent molecular bonding Low melting pointsLow melting points-due to generally weak -due to generally weak

attractive forces between molecules There attractive forces between molecules There are exceptions to this rule (eg Iare exceptions to this rule (eg I22 melts at melts at 11411400C but decomposes at 1000C but decomposes at 100000C) C)

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

SoftSoft-due to weak forces existing between -due to weak forces existing between moleculesmolecules

Properties associated with Properties associated with bond typesbond types

Covalent Network bondingCovalent Network bonding Very high melting points and boiling Very high melting points and boiling

pointspoints-due to strong covalent bonding -due to strong covalent bonding which form rigid 3-D structureswhich form rigid 3-D structures

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

Extremely hardExtremely hard- due to strong covalent - due to strong covalent bonding which form rigid 3-D structuresbonding which form rigid 3-D structures

The Chemical EarthThe Chemical Earth

Compiled by Robert Slider (2006)

Please share this resource with others

Decomposition Reactions-Decomposition Reactions-examplesexamples

HeatHeatSolid Solid copper nitratecopper nitrate decomposes to solid decomposes to solid copper copper

oxideoxide nitrogen dioxidenitrogen dioxide and and oxygenoxygen gases gases

ElectricityElectricityMolten Molten lead bromidelead bromide (400 (40000C) forms C) forms brominebromine gas at gas at

the +ve electrode and liquid the +ve electrode and liquid leadlead at the ndashve at the ndashve electrodeelectrode

LightLightSolid Solid silver chloridesilver chloride decomposes to decomposes to silversilver metal and metal and

chlorinechlorine gas (decomposition of silver compounds gas (decomposition of silver compounds is the basis of photography development)is the basis of photography development)

Synthesis ReactionsSynthesis ReactionsEnergy releasedEnergy released

A synthesis or combination reaction A synthesis or combination reaction involves the combination of two or involves the combination of two or more pure substances When a more pure substances When a compound is formed from its compound is formed from its elements it is known as a elements it is known as a direct direct combination reactioncombination reaction These These reactions normally release energy reactions normally release energy

A + B A + B AB + energy AB + energy

Synthesis reactions - Synthesis reactions - examplesexamples

MagnesiumMagnesium burns in air ( burns in air (oxygenoxygen) to produce ) to produce magnesium oxidemagnesium oxide (light and heat energy (light and heat energy released)released)

HydrogenHydrogen and and oxygenoxygen combine in an combine in an explosive reaction to produce explosive reaction to produce waterwater (much (much energy released)energy released)

CopperCopper metal combines with yellow metal combines with yellow sulphursulphur when heated to produce when heated to produce copper (I) copper (I) sulphidesulphide (much heat energy is released) (much heat energy is released)

Decomposition and Decomposition and SynthesisSynthesis

Everyday ApplicationsEveryday ApplicationsDecompositionDecomposition

Air bags ndash sodium azide Air bags ndash sodium azide (NaN(NaN33) decomposes to ) decomposes to sodium and nitrogen gas by sodium and nitrogen gas by ignition with a detonating ignition with a detonating capcap

Limestone (primarily CaCOLimestone (primarily CaCO33) ) ndash decomposes to calcium ndash decomposes to calcium oxide and carbon dioxide by oxide and carbon dioxide by heating to make lime (CaO) heating to make lime (CaO) cement and glasscement and glass

Aluminium - the industrial Aluminium - the industrial process of electrolysing process of electrolysing aluminium oxide produces aluminium oxide produces aluminium metalaluminium metal

SynthesisSynthesis Rust ndash iron and oxygen Rust ndash iron and oxygen

combine in the presence of combine in the presence of water to form iron (III) oxidewater to form iron (III) oxide

Burning coke (primarily Burning coke (primarily carbon) is used as a fuel in carbon) is used as a fuel in smelting iron ore in a blast smelting iron ore in a blast furnace during the steel furnace during the steel making process making process

Pollutants - NO (nitric oxide Pollutants - NO (nitric oxide or nitrogen monoxide) and or nitrogen monoxide) and NO2 (nitrogen dioxide) are NO2 (nitrogen dioxide) are formed inside the formed inside the combustion chambers of cars combustion chambers of cars from nitrogen and oxygen from nitrogen and oxygen gasesgases

82 The Chemical Earth82 The Chemical Earth

Focus 5Focus 5

The properties of elements and The properties of elements and compounds are determined by compounds are determined by

their bonding and structuretheir bonding and structure

Properties of elements and Properties of elements and their compounds are very their compounds are very

differentdifferent8Fe(s) + S8Fe(s) + S88(s) + heat (s) + heat 8FeS(s) 8FeS(s)

substancsubstancee

colourcolour Melting Melting point point ((00C)C)

Boiling Boiling point point ((00C)C)

Density Density (gcm(gcm33))

magneticmagnetic

IronIron GreyGrey 15351535 27502750 7979 yesyes

SulphurSulphur YellowYellow 113113 445445 2121 nono

Iron (II) Iron (II) sulphidesulphide

Yellow-Yellow-goldgold

11941194 -- 484484 nono

Properties of elements Properties of elements compounds and mixtures compounds and mixtures

are very differentare very differentAluminiumAluminiumPhysical propertiesPhysical properties MP = 660MP = 66000CC Density = 27 gcmDensity = 27 gcm3 3

Conductivity = 378 x10Conductivity = 378 x1066 Smiddotm-1 Smiddotm-1 (20 degC)(20 degC)

Chemical propertiesChemical properties 4Al(s)+ 3O4Al(s)+ 3O22(g) (g) 2Al 2Al22OO33(s)(s) 2Al(s) + 6HCl(g) 2Al(s) + 6HCl(g) 2AlCl 2AlCl33(aq) (aq)

+ 3H+ 3H22(g)(g)

OxygenOxygenPhysical propertiesPhysical properties MP = -219MP = -21900CC Density = 00013 gcmDensity = 00013 gcm33

Conductivity = non-conductorConductivity = non-conductor

Bauxite ore Bauxite ore (Al(Al22OO33xHxH22O)O)Physical propertiesPhysical properties MP = 2045MP = 204500CC Density = 35-4 gcmDensity = 35-4 gcm33

Conductivity = non-conductorConductivity = non-conductor

Chemical propertiesChemical properties AlAl22OO33(s) + 2NaOH + 3H(s) + 2NaOH + 3H22O(l) O(l)

2Na[Al(OH)2Na[Al(OH)44](aq) (Bayer process)](aq) (Bayer process)

NB Bauxite is essentially an impure NB Bauxite is essentially an impure aluminium oxide The major aluminium oxide The major impurities include iron oxides impurities include iron oxides silicon dioxide and titanium silicon dioxide and titanium dioxide The impurities remain as dioxide The impurities remain as solids and do not react with solids and do not react with NaOH This process removes NaOH This process removes these impuritiesthese impurities

Structure of metalsStructure of metals

Metals can be described as three-Metals can be described as three-dimensional lattices of positive ions in a dimensional lattices of positive ions in a sea of delocalised electrons sea of delocalised electrons

Covalent BondingCovalent Bonding Covalent Molecular-strong Covalent Molecular-strong

bonds weak bonds weak intermolecular forces intermolecular forces holding molecules holding molecules togethertogether

Covalent Network-Covalent Network-covalent bonding lattice covalent bonding lattice that extends indefinitely that extends indefinitely throughout the crystalthroughout the crystal

Ionic bondingIonic bonding

No discreet molecules are formed in No discreet molecules are formed in ionic bonding due to electrostatic ionic bonding due to electrostatic forces holding the atoms together forces holding the atoms together They form a continuing 3D latticeThey form a continuing 3D lattice

-- --

-- -- --

--

-- --

---- --++

++

++

++++

++

++

++++++

Properties associated with Properties associated with bond typesbond types

Metallic bondingMetallic bonding High melting pointsHigh melting points-due to strong attraction between -due to strong attraction between

positively charged metal ions and delocalized positively charged metal ions and delocalized electrons The higher the valency the stronger the electrons The higher the valency the stronger the bond eg Cabond eg Ca2+2+ is stronger than K is stronger than K++

Good conductors of heat and electricityGood conductors of heat and electricity-due to the high -due to the high mobility of delocalized electrons Electrons enter and mobility of delocalized electrons Electrons enter and leave a metal easilyleave a metal easily

Malleable and ductileMalleable and ductile-due to delocalized electrons not -due to delocalized electrons not belonging to any particular metal atom Therefore one belonging to any particular metal atom Therefore one layer of ions can slide over another without disrupting layer of ions can slide over another without disrupting the bond between metal atoms The electrons and the bond between metal atoms The electrons and metal ions simply rearrangemetal ions simply rearrange

HardnessHardness- tend to be hard due to tightly packed atoms- tend to be hard due to tightly packed atoms

Properties associated with Properties associated with bond typesbond types

Ionic bondingIonic bonding High melting pointsHigh melting points-due to strong electrostatic attraction -due to strong electrostatic attraction

between anions and cationsbetween anions and cations

Non-conductors of electricity in solid stateNon-conductors of electricity in solid state-due to -due to oppositely charged particles which are in fixed positionsoppositely charged particles which are in fixed positions

Conductors in the liquid (molten) stateConductors in the liquid (molten) state-due to the ions -due to the ions being able to move freely through the liquidbeing able to move freely through the liquid

HardnessHardness-due to strong electrostatic attraction between -due to strong electrostatic attraction between oppositely charged particlesoppositely charged particles

BrittleBrittle-due to the fixed location of oppositely charged -due to the fixed location of oppositely charged particles Displacement of ions moves them closer to ions particles Displacement of ions moves them closer to ions of a similar charge which increases the repulsive forces of a similar charge which increases the repulsive forces along the fracturealong the fracture

Properties associated with Properties associated with bond typesbond types

Covalent molecular bondingCovalent molecular bonding Low melting pointsLow melting points-due to generally weak -due to generally weak

attractive forces between molecules There attractive forces between molecules There are exceptions to this rule (eg Iare exceptions to this rule (eg I22 melts at melts at 11411400C but decomposes at 1000C but decomposes at 100000C) C)

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

SoftSoft-due to weak forces existing between -due to weak forces existing between moleculesmolecules

Properties associated with Properties associated with bond typesbond types

Covalent Network bondingCovalent Network bonding Very high melting points and boiling Very high melting points and boiling

pointspoints-due to strong covalent bonding -due to strong covalent bonding which form rigid 3-D structureswhich form rigid 3-D structures

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

Extremely hardExtremely hard- due to strong covalent - due to strong covalent bonding which form rigid 3-D structuresbonding which form rigid 3-D structures

The Chemical EarthThe Chemical Earth

Compiled by Robert Slider (2006)

Please share this resource with others

Synthesis ReactionsSynthesis ReactionsEnergy releasedEnergy released

A synthesis or combination reaction A synthesis or combination reaction involves the combination of two or involves the combination of two or more pure substances When a more pure substances When a compound is formed from its compound is formed from its elements it is known as a elements it is known as a direct direct combination reactioncombination reaction These These reactions normally release energy reactions normally release energy

A + B A + B AB + energy AB + energy

Synthesis reactions - Synthesis reactions - examplesexamples

MagnesiumMagnesium burns in air ( burns in air (oxygenoxygen) to produce ) to produce magnesium oxidemagnesium oxide (light and heat energy (light and heat energy released)released)

HydrogenHydrogen and and oxygenoxygen combine in an combine in an explosive reaction to produce explosive reaction to produce waterwater (much (much energy released)energy released)

CopperCopper metal combines with yellow metal combines with yellow sulphursulphur when heated to produce when heated to produce copper (I) copper (I) sulphidesulphide (much heat energy is released) (much heat energy is released)

Decomposition and Decomposition and SynthesisSynthesis

Everyday ApplicationsEveryday ApplicationsDecompositionDecomposition

Air bags ndash sodium azide Air bags ndash sodium azide (NaN(NaN33) decomposes to ) decomposes to sodium and nitrogen gas by sodium and nitrogen gas by ignition with a detonating ignition with a detonating capcap

Limestone (primarily CaCOLimestone (primarily CaCO33) ) ndash decomposes to calcium ndash decomposes to calcium oxide and carbon dioxide by oxide and carbon dioxide by heating to make lime (CaO) heating to make lime (CaO) cement and glasscement and glass

Aluminium - the industrial Aluminium - the industrial process of electrolysing process of electrolysing aluminium oxide produces aluminium oxide produces aluminium metalaluminium metal

SynthesisSynthesis Rust ndash iron and oxygen Rust ndash iron and oxygen

combine in the presence of combine in the presence of water to form iron (III) oxidewater to form iron (III) oxide

Burning coke (primarily Burning coke (primarily carbon) is used as a fuel in carbon) is used as a fuel in smelting iron ore in a blast smelting iron ore in a blast furnace during the steel furnace during the steel making process making process

Pollutants - NO (nitric oxide Pollutants - NO (nitric oxide or nitrogen monoxide) and or nitrogen monoxide) and NO2 (nitrogen dioxide) are NO2 (nitrogen dioxide) are formed inside the formed inside the combustion chambers of cars combustion chambers of cars from nitrogen and oxygen from nitrogen and oxygen gasesgases

82 The Chemical Earth82 The Chemical Earth

Focus 5Focus 5

The properties of elements and The properties of elements and compounds are determined by compounds are determined by

their bonding and structuretheir bonding and structure

Properties of elements and Properties of elements and their compounds are very their compounds are very

differentdifferent8Fe(s) + S8Fe(s) + S88(s) + heat (s) + heat 8FeS(s) 8FeS(s)

substancsubstancee

colourcolour Melting Melting point point ((00C)C)

Boiling Boiling point point ((00C)C)

Density Density (gcm(gcm33))

magneticmagnetic

IronIron GreyGrey 15351535 27502750 7979 yesyes

SulphurSulphur YellowYellow 113113 445445 2121 nono

Iron (II) Iron (II) sulphidesulphide

Yellow-Yellow-goldgold

11941194 -- 484484 nono

Properties of elements Properties of elements compounds and mixtures compounds and mixtures

are very differentare very differentAluminiumAluminiumPhysical propertiesPhysical properties MP = 660MP = 66000CC Density = 27 gcmDensity = 27 gcm3 3

Conductivity = 378 x10Conductivity = 378 x1066 Smiddotm-1 Smiddotm-1 (20 degC)(20 degC)

Chemical propertiesChemical properties 4Al(s)+ 3O4Al(s)+ 3O22(g) (g) 2Al 2Al22OO33(s)(s) 2Al(s) + 6HCl(g) 2Al(s) + 6HCl(g) 2AlCl 2AlCl33(aq) (aq)

+ 3H+ 3H22(g)(g)

OxygenOxygenPhysical propertiesPhysical properties MP = -219MP = -21900CC Density = 00013 gcmDensity = 00013 gcm33

Conductivity = non-conductorConductivity = non-conductor

Bauxite ore Bauxite ore (Al(Al22OO33xHxH22O)O)Physical propertiesPhysical properties MP = 2045MP = 204500CC Density = 35-4 gcmDensity = 35-4 gcm33

Conductivity = non-conductorConductivity = non-conductor

Chemical propertiesChemical properties AlAl22OO33(s) + 2NaOH + 3H(s) + 2NaOH + 3H22O(l) O(l)

2Na[Al(OH)2Na[Al(OH)44](aq) (Bayer process)](aq) (Bayer process)

NB Bauxite is essentially an impure NB Bauxite is essentially an impure aluminium oxide The major aluminium oxide The major impurities include iron oxides impurities include iron oxides silicon dioxide and titanium silicon dioxide and titanium dioxide The impurities remain as dioxide The impurities remain as solids and do not react with solids and do not react with NaOH This process removes NaOH This process removes these impuritiesthese impurities

Structure of metalsStructure of metals

Metals can be described as three-Metals can be described as three-dimensional lattices of positive ions in a dimensional lattices of positive ions in a sea of delocalised electrons sea of delocalised electrons

Covalent BondingCovalent Bonding Covalent Molecular-strong Covalent Molecular-strong

bonds weak bonds weak intermolecular forces intermolecular forces holding molecules holding molecules togethertogether

Covalent Network-Covalent Network-covalent bonding lattice covalent bonding lattice that extends indefinitely that extends indefinitely throughout the crystalthroughout the crystal

Ionic bondingIonic bonding

No discreet molecules are formed in No discreet molecules are formed in ionic bonding due to electrostatic ionic bonding due to electrostatic forces holding the atoms together forces holding the atoms together They form a continuing 3D latticeThey form a continuing 3D lattice

-- --

-- -- --

--

-- --

---- --++

++

++

++++

++

++

++++++

Properties associated with Properties associated with bond typesbond types

Metallic bondingMetallic bonding High melting pointsHigh melting points-due to strong attraction between -due to strong attraction between

positively charged metal ions and delocalized positively charged metal ions and delocalized electrons The higher the valency the stronger the electrons The higher the valency the stronger the bond eg Cabond eg Ca2+2+ is stronger than K is stronger than K++

Good conductors of heat and electricityGood conductors of heat and electricity-due to the high -due to the high mobility of delocalized electrons Electrons enter and mobility of delocalized electrons Electrons enter and leave a metal easilyleave a metal easily

Malleable and ductileMalleable and ductile-due to delocalized electrons not -due to delocalized electrons not belonging to any particular metal atom Therefore one belonging to any particular metal atom Therefore one layer of ions can slide over another without disrupting layer of ions can slide over another without disrupting the bond between metal atoms The electrons and the bond between metal atoms The electrons and metal ions simply rearrangemetal ions simply rearrange

HardnessHardness- tend to be hard due to tightly packed atoms- tend to be hard due to tightly packed atoms

Properties associated with Properties associated with bond typesbond types

Ionic bondingIonic bonding High melting pointsHigh melting points-due to strong electrostatic attraction -due to strong electrostatic attraction

between anions and cationsbetween anions and cations

Non-conductors of electricity in solid stateNon-conductors of electricity in solid state-due to -due to oppositely charged particles which are in fixed positionsoppositely charged particles which are in fixed positions

Conductors in the liquid (molten) stateConductors in the liquid (molten) state-due to the ions -due to the ions being able to move freely through the liquidbeing able to move freely through the liquid

HardnessHardness-due to strong electrostatic attraction between -due to strong electrostatic attraction between oppositely charged particlesoppositely charged particles

BrittleBrittle-due to the fixed location of oppositely charged -due to the fixed location of oppositely charged particles Displacement of ions moves them closer to ions particles Displacement of ions moves them closer to ions of a similar charge which increases the repulsive forces of a similar charge which increases the repulsive forces along the fracturealong the fracture

Properties associated with Properties associated with bond typesbond types

Covalent molecular bondingCovalent molecular bonding Low melting pointsLow melting points-due to generally weak -due to generally weak

attractive forces between molecules There attractive forces between molecules There are exceptions to this rule (eg Iare exceptions to this rule (eg I22 melts at melts at 11411400C but decomposes at 1000C but decomposes at 100000C) C)

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

SoftSoft-due to weak forces existing between -due to weak forces existing between moleculesmolecules

Properties associated with Properties associated with bond typesbond types

Covalent Network bondingCovalent Network bonding Very high melting points and boiling Very high melting points and boiling

pointspoints-due to strong covalent bonding -due to strong covalent bonding which form rigid 3-D structureswhich form rigid 3-D structures

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

Extremely hardExtremely hard- due to strong covalent - due to strong covalent bonding which form rigid 3-D structuresbonding which form rigid 3-D structures

The Chemical EarthThe Chemical Earth

Compiled by Robert Slider (2006)

Please share this resource with others

Synthesis reactions - Synthesis reactions - examplesexamples

MagnesiumMagnesium burns in air ( burns in air (oxygenoxygen) to produce ) to produce magnesium oxidemagnesium oxide (light and heat energy (light and heat energy released)released)

HydrogenHydrogen and and oxygenoxygen combine in an combine in an explosive reaction to produce explosive reaction to produce waterwater (much (much energy released)energy released)

CopperCopper metal combines with yellow metal combines with yellow sulphursulphur when heated to produce when heated to produce copper (I) copper (I) sulphidesulphide (much heat energy is released) (much heat energy is released)

Decomposition and Decomposition and SynthesisSynthesis

Everyday ApplicationsEveryday ApplicationsDecompositionDecomposition

Air bags ndash sodium azide Air bags ndash sodium azide (NaN(NaN33) decomposes to ) decomposes to sodium and nitrogen gas by sodium and nitrogen gas by ignition with a detonating ignition with a detonating capcap

Limestone (primarily CaCOLimestone (primarily CaCO33) ) ndash decomposes to calcium ndash decomposes to calcium oxide and carbon dioxide by oxide and carbon dioxide by heating to make lime (CaO) heating to make lime (CaO) cement and glasscement and glass

Aluminium - the industrial Aluminium - the industrial process of electrolysing process of electrolysing aluminium oxide produces aluminium oxide produces aluminium metalaluminium metal

SynthesisSynthesis Rust ndash iron and oxygen Rust ndash iron and oxygen

combine in the presence of combine in the presence of water to form iron (III) oxidewater to form iron (III) oxide

Burning coke (primarily Burning coke (primarily carbon) is used as a fuel in carbon) is used as a fuel in smelting iron ore in a blast smelting iron ore in a blast furnace during the steel furnace during the steel making process making process

Pollutants - NO (nitric oxide Pollutants - NO (nitric oxide or nitrogen monoxide) and or nitrogen monoxide) and NO2 (nitrogen dioxide) are NO2 (nitrogen dioxide) are formed inside the formed inside the combustion chambers of cars combustion chambers of cars from nitrogen and oxygen from nitrogen and oxygen gasesgases

82 The Chemical Earth82 The Chemical Earth

Focus 5Focus 5

The properties of elements and The properties of elements and compounds are determined by compounds are determined by

their bonding and structuretheir bonding and structure

Properties of elements and Properties of elements and their compounds are very their compounds are very

differentdifferent8Fe(s) + S8Fe(s) + S88(s) + heat (s) + heat 8FeS(s) 8FeS(s)

substancsubstancee

colourcolour Melting Melting point point ((00C)C)

Boiling Boiling point point ((00C)C)

Density Density (gcm(gcm33))

magneticmagnetic

IronIron GreyGrey 15351535 27502750 7979 yesyes

SulphurSulphur YellowYellow 113113 445445 2121 nono

Iron (II) Iron (II) sulphidesulphide

Yellow-Yellow-goldgold

11941194 -- 484484 nono

Properties of elements Properties of elements compounds and mixtures compounds and mixtures

are very differentare very differentAluminiumAluminiumPhysical propertiesPhysical properties MP = 660MP = 66000CC Density = 27 gcmDensity = 27 gcm3 3

Conductivity = 378 x10Conductivity = 378 x1066 Smiddotm-1 Smiddotm-1 (20 degC)(20 degC)

Chemical propertiesChemical properties 4Al(s)+ 3O4Al(s)+ 3O22(g) (g) 2Al 2Al22OO33(s)(s) 2Al(s) + 6HCl(g) 2Al(s) + 6HCl(g) 2AlCl 2AlCl33(aq) (aq)

+ 3H+ 3H22(g)(g)

OxygenOxygenPhysical propertiesPhysical properties MP = -219MP = -21900CC Density = 00013 gcmDensity = 00013 gcm33

Conductivity = non-conductorConductivity = non-conductor

Bauxite ore Bauxite ore (Al(Al22OO33xHxH22O)O)Physical propertiesPhysical properties MP = 2045MP = 204500CC Density = 35-4 gcmDensity = 35-4 gcm33

Conductivity = non-conductorConductivity = non-conductor

Chemical propertiesChemical properties AlAl22OO33(s) + 2NaOH + 3H(s) + 2NaOH + 3H22O(l) O(l)

2Na[Al(OH)2Na[Al(OH)44](aq) (Bayer process)](aq) (Bayer process)

NB Bauxite is essentially an impure NB Bauxite is essentially an impure aluminium oxide The major aluminium oxide The major impurities include iron oxides impurities include iron oxides silicon dioxide and titanium silicon dioxide and titanium dioxide The impurities remain as dioxide The impurities remain as solids and do not react with solids and do not react with NaOH This process removes NaOH This process removes these impuritiesthese impurities

Structure of metalsStructure of metals

Metals can be described as three-Metals can be described as three-dimensional lattices of positive ions in a dimensional lattices of positive ions in a sea of delocalised electrons sea of delocalised electrons

Covalent BondingCovalent Bonding Covalent Molecular-strong Covalent Molecular-strong

bonds weak bonds weak intermolecular forces intermolecular forces holding molecules holding molecules togethertogether

Covalent Network-Covalent Network-covalent bonding lattice covalent bonding lattice that extends indefinitely that extends indefinitely throughout the crystalthroughout the crystal

Ionic bondingIonic bonding

No discreet molecules are formed in No discreet molecules are formed in ionic bonding due to electrostatic ionic bonding due to electrostatic forces holding the atoms together forces holding the atoms together They form a continuing 3D latticeThey form a continuing 3D lattice

-- --

-- -- --

--

-- --

---- --++

++

++

++++

++

++

++++++

Properties associated with Properties associated with bond typesbond types

Metallic bondingMetallic bonding High melting pointsHigh melting points-due to strong attraction between -due to strong attraction between

positively charged metal ions and delocalized positively charged metal ions and delocalized electrons The higher the valency the stronger the electrons The higher the valency the stronger the bond eg Cabond eg Ca2+2+ is stronger than K is stronger than K++

Good conductors of heat and electricityGood conductors of heat and electricity-due to the high -due to the high mobility of delocalized electrons Electrons enter and mobility of delocalized electrons Electrons enter and leave a metal easilyleave a metal easily

Malleable and ductileMalleable and ductile-due to delocalized electrons not -due to delocalized electrons not belonging to any particular metal atom Therefore one belonging to any particular metal atom Therefore one layer of ions can slide over another without disrupting layer of ions can slide over another without disrupting the bond between metal atoms The electrons and the bond between metal atoms The electrons and metal ions simply rearrangemetal ions simply rearrange

HardnessHardness- tend to be hard due to tightly packed atoms- tend to be hard due to tightly packed atoms

Properties associated with Properties associated with bond typesbond types

Ionic bondingIonic bonding High melting pointsHigh melting points-due to strong electrostatic attraction -due to strong electrostatic attraction

between anions and cationsbetween anions and cations

Non-conductors of electricity in solid stateNon-conductors of electricity in solid state-due to -due to oppositely charged particles which are in fixed positionsoppositely charged particles which are in fixed positions

Conductors in the liquid (molten) stateConductors in the liquid (molten) state-due to the ions -due to the ions being able to move freely through the liquidbeing able to move freely through the liquid

HardnessHardness-due to strong electrostatic attraction between -due to strong electrostatic attraction between oppositely charged particlesoppositely charged particles

BrittleBrittle-due to the fixed location of oppositely charged -due to the fixed location of oppositely charged particles Displacement of ions moves them closer to ions particles Displacement of ions moves them closer to ions of a similar charge which increases the repulsive forces of a similar charge which increases the repulsive forces along the fracturealong the fracture

Properties associated with Properties associated with bond typesbond types

Covalent molecular bondingCovalent molecular bonding Low melting pointsLow melting points-due to generally weak -due to generally weak

attractive forces between molecules There attractive forces between molecules There are exceptions to this rule (eg Iare exceptions to this rule (eg I22 melts at melts at 11411400C but decomposes at 1000C but decomposes at 100000C) C)

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

SoftSoft-due to weak forces existing between -due to weak forces existing between moleculesmolecules

Properties associated with Properties associated with bond typesbond types

Covalent Network bondingCovalent Network bonding Very high melting points and boiling Very high melting points and boiling

pointspoints-due to strong covalent bonding -due to strong covalent bonding which form rigid 3-D structureswhich form rigid 3-D structures

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

Extremely hardExtremely hard- due to strong covalent - due to strong covalent bonding which form rigid 3-D structuresbonding which form rigid 3-D structures

The Chemical EarthThe Chemical Earth

Compiled by Robert Slider (2006)

Please share this resource with others

Decomposition and Decomposition and SynthesisSynthesis

Everyday ApplicationsEveryday ApplicationsDecompositionDecomposition

Air bags ndash sodium azide Air bags ndash sodium azide (NaN(NaN33) decomposes to ) decomposes to sodium and nitrogen gas by sodium and nitrogen gas by ignition with a detonating ignition with a detonating capcap

Limestone (primarily CaCOLimestone (primarily CaCO33) ) ndash decomposes to calcium ndash decomposes to calcium oxide and carbon dioxide by oxide and carbon dioxide by heating to make lime (CaO) heating to make lime (CaO) cement and glasscement and glass

Aluminium - the industrial Aluminium - the industrial process of electrolysing process of electrolysing aluminium oxide produces aluminium oxide produces aluminium metalaluminium metal

SynthesisSynthesis Rust ndash iron and oxygen Rust ndash iron and oxygen

combine in the presence of combine in the presence of water to form iron (III) oxidewater to form iron (III) oxide

Burning coke (primarily Burning coke (primarily carbon) is used as a fuel in carbon) is used as a fuel in smelting iron ore in a blast smelting iron ore in a blast furnace during the steel furnace during the steel making process making process

Pollutants - NO (nitric oxide Pollutants - NO (nitric oxide or nitrogen monoxide) and or nitrogen monoxide) and NO2 (nitrogen dioxide) are NO2 (nitrogen dioxide) are formed inside the formed inside the combustion chambers of cars combustion chambers of cars from nitrogen and oxygen from nitrogen and oxygen gasesgases

82 The Chemical Earth82 The Chemical Earth

Focus 5Focus 5

The properties of elements and The properties of elements and compounds are determined by compounds are determined by

their bonding and structuretheir bonding and structure

Properties of elements and Properties of elements and their compounds are very their compounds are very

differentdifferent8Fe(s) + S8Fe(s) + S88(s) + heat (s) + heat 8FeS(s) 8FeS(s)

substancsubstancee

colourcolour Melting Melting point point ((00C)C)

Boiling Boiling point point ((00C)C)

Density Density (gcm(gcm33))

magneticmagnetic

IronIron GreyGrey 15351535 27502750 7979 yesyes

SulphurSulphur YellowYellow 113113 445445 2121 nono

Iron (II) Iron (II) sulphidesulphide

Yellow-Yellow-goldgold

11941194 -- 484484 nono

Properties of elements Properties of elements compounds and mixtures compounds and mixtures

are very differentare very differentAluminiumAluminiumPhysical propertiesPhysical properties MP = 660MP = 66000CC Density = 27 gcmDensity = 27 gcm3 3

Conductivity = 378 x10Conductivity = 378 x1066 Smiddotm-1 Smiddotm-1 (20 degC)(20 degC)

Chemical propertiesChemical properties 4Al(s)+ 3O4Al(s)+ 3O22(g) (g) 2Al 2Al22OO33(s)(s) 2Al(s) + 6HCl(g) 2Al(s) + 6HCl(g) 2AlCl 2AlCl33(aq) (aq)

+ 3H+ 3H22(g)(g)

OxygenOxygenPhysical propertiesPhysical properties MP = -219MP = -21900CC Density = 00013 gcmDensity = 00013 gcm33

Conductivity = non-conductorConductivity = non-conductor

Bauxite ore Bauxite ore (Al(Al22OO33xHxH22O)O)Physical propertiesPhysical properties MP = 2045MP = 204500CC Density = 35-4 gcmDensity = 35-4 gcm33

Conductivity = non-conductorConductivity = non-conductor

Chemical propertiesChemical properties AlAl22OO33(s) + 2NaOH + 3H(s) + 2NaOH + 3H22O(l) O(l)

2Na[Al(OH)2Na[Al(OH)44](aq) (Bayer process)](aq) (Bayer process)

NB Bauxite is essentially an impure NB Bauxite is essentially an impure aluminium oxide The major aluminium oxide The major impurities include iron oxides impurities include iron oxides silicon dioxide and titanium silicon dioxide and titanium dioxide The impurities remain as dioxide The impurities remain as solids and do not react with solids and do not react with NaOH This process removes NaOH This process removes these impuritiesthese impurities

Structure of metalsStructure of metals

Metals can be described as three-Metals can be described as three-dimensional lattices of positive ions in a dimensional lattices of positive ions in a sea of delocalised electrons sea of delocalised electrons

Covalent BondingCovalent Bonding Covalent Molecular-strong Covalent Molecular-strong

bonds weak bonds weak intermolecular forces intermolecular forces holding molecules holding molecules togethertogether

Covalent Network-Covalent Network-covalent bonding lattice covalent bonding lattice that extends indefinitely that extends indefinitely throughout the crystalthroughout the crystal

Ionic bondingIonic bonding

No discreet molecules are formed in No discreet molecules are formed in ionic bonding due to electrostatic ionic bonding due to electrostatic forces holding the atoms together forces holding the atoms together They form a continuing 3D latticeThey form a continuing 3D lattice

-- --

-- -- --

--

-- --

---- --++

++

++

++++

++

++

++++++

Properties associated with Properties associated with bond typesbond types

Metallic bondingMetallic bonding High melting pointsHigh melting points-due to strong attraction between -due to strong attraction between

positively charged metal ions and delocalized positively charged metal ions and delocalized electrons The higher the valency the stronger the electrons The higher the valency the stronger the bond eg Cabond eg Ca2+2+ is stronger than K is stronger than K++

Good conductors of heat and electricityGood conductors of heat and electricity-due to the high -due to the high mobility of delocalized electrons Electrons enter and mobility of delocalized electrons Electrons enter and leave a metal easilyleave a metal easily

Malleable and ductileMalleable and ductile-due to delocalized electrons not -due to delocalized electrons not belonging to any particular metal atom Therefore one belonging to any particular metal atom Therefore one layer of ions can slide over another without disrupting layer of ions can slide over another without disrupting the bond between metal atoms The electrons and the bond between metal atoms The electrons and metal ions simply rearrangemetal ions simply rearrange

HardnessHardness- tend to be hard due to tightly packed atoms- tend to be hard due to tightly packed atoms

Properties associated with Properties associated with bond typesbond types

Ionic bondingIonic bonding High melting pointsHigh melting points-due to strong electrostatic attraction -due to strong electrostatic attraction

between anions and cationsbetween anions and cations

Non-conductors of electricity in solid stateNon-conductors of electricity in solid state-due to -due to oppositely charged particles which are in fixed positionsoppositely charged particles which are in fixed positions

Conductors in the liquid (molten) stateConductors in the liquid (molten) state-due to the ions -due to the ions being able to move freely through the liquidbeing able to move freely through the liquid

HardnessHardness-due to strong electrostatic attraction between -due to strong electrostatic attraction between oppositely charged particlesoppositely charged particles

BrittleBrittle-due to the fixed location of oppositely charged -due to the fixed location of oppositely charged particles Displacement of ions moves them closer to ions particles Displacement of ions moves them closer to ions of a similar charge which increases the repulsive forces of a similar charge which increases the repulsive forces along the fracturealong the fracture

Properties associated with Properties associated with bond typesbond types

Covalent molecular bondingCovalent molecular bonding Low melting pointsLow melting points-due to generally weak -due to generally weak

attractive forces between molecules There attractive forces between molecules There are exceptions to this rule (eg Iare exceptions to this rule (eg I22 melts at melts at 11411400C but decomposes at 1000C but decomposes at 100000C) C)

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

SoftSoft-due to weak forces existing between -due to weak forces existing between moleculesmolecules

Properties associated with Properties associated with bond typesbond types

Covalent Network bondingCovalent Network bonding Very high melting points and boiling Very high melting points and boiling

pointspoints-due to strong covalent bonding -due to strong covalent bonding which form rigid 3-D structureswhich form rigid 3-D structures

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

Extremely hardExtremely hard- due to strong covalent - due to strong covalent bonding which form rigid 3-D structuresbonding which form rigid 3-D structures

The Chemical EarthThe Chemical Earth

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Please share this resource with others

82 The Chemical Earth82 The Chemical Earth

Focus 5Focus 5

The properties of elements and The properties of elements and compounds are determined by compounds are determined by

their bonding and structuretheir bonding and structure

Properties of elements and Properties of elements and their compounds are very their compounds are very

differentdifferent8Fe(s) + S8Fe(s) + S88(s) + heat (s) + heat 8FeS(s) 8FeS(s)

substancsubstancee

colourcolour Melting Melting point point ((00C)C)

Boiling Boiling point point ((00C)C)

Density Density (gcm(gcm33))

magneticmagnetic

IronIron GreyGrey 15351535 27502750 7979 yesyes

SulphurSulphur YellowYellow 113113 445445 2121 nono

Iron (II) Iron (II) sulphidesulphide

Yellow-Yellow-goldgold

11941194 -- 484484 nono

Properties of elements Properties of elements compounds and mixtures compounds and mixtures

are very differentare very differentAluminiumAluminiumPhysical propertiesPhysical properties MP = 660MP = 66000CC Density = 27 gcmDensity = 27 gcm3 3

Conductivity = 378 x10Conductivity = 378 x1066 Smiddotm-1 Smiddotm-1 (20 degC)(20 degC)

Chemical propertiesChemical properties 4Al(s)+ 3O4Al(s)+ 3O22(g) (g) 2Al 2Al22OO33(s)(s) 2Al(s) + 6HCl(g) 2Al(s) + 6HCl(g) 2AlCl 2AlCl33(aq) (aq)

+ 3H+ 3H22(g)(g)

OxygenOxygenPhysical propertiesPhysical properties MP = -219MP = -21900CC Density = 00013 gcmDensity = 00013 gcm33

Conductivity = non-conductorConductivity = non-conductor

Bauxite ore Bauxite ore (Al(Al22OO33xHxH22O)O)Physical propertiesPhysical properties MP = 2045MP = 204500CC Density = 35-4 gcmDensity = 35-4 gcm33

Conductivity = non-conductorConductivity = non-conductor

Chemical propertiesChemical properties AlAl22OO33(s) + 2NaOH + 3H(s) + 2NaOH + 3H22O(l) O(l)

2Na[Al(OH)2Na[Al(OH)44](aq) (Bayer process)](aq) (Bayer process)

NB Bauxite is essentially an impure NB Bauxite is essentially an impure aluminium oxide The major aluminium oxide The major impurities include iron oxides impurities include iron oxides silicon dioxide and titanium silicon dioxide and titanium dioxide The impurities remain as dioxide The impurities remain as solids and do not react with solids and do not react with NaOH This process removes NaOH This process removes these impuritiesthese impurities

Structure of metalsStructure of metals

Metals can be described as three-Metals can be described as three-dimensional lattices of positive ions in a dimensional lattices of positive ions in a sea of delocalised electrons sea of delocalised electrons

Covalent BondingCovalent Bonding Covalent Molecular-strong Covalent Molecular-strong

bonds weak bonds weak intermolecular forces intermolecular forces holding molecules holding molecules togethertogether

Covalent Network-Covalent Network-covalent bonding lattice covalent bonding lattice that extends indefinitely that extends indefinitely throughout the crystalthroughout the crystal

Ionic bondingIonic bonding

No discreet molecules are formed in No discreet molecules are formed in ionic bonding due to electrostatic ionic bonding due to electrostatic forces holding the atoms together forces holding the atoms together They form a continuing 3D latticeThey form a continuing 3D lattice

-- --

-- -- --

--

-- --

---- --++

++

++

++++

++

++

++++++

Properties associated with Properties associated with bond typesbond types

Metallic bondingMetallic bonding High melting pointsHigh melting points-due to strong attraction between -due to strong attraction between

positively charged metal ions and delocalized positively charged metal ions and delocalized electrons The higher the valency the stronger the electrons The higher the valency the stronger the bond eg Cabond eg Ca2+2+ is stronger than K is stronger than K++

Good conductors of heat and electricityGood conductors of heat and electricity-due to the high -due to the high mobility of delocalized electrons Electrons enter and mobility of delocalized electrons Electrons enter and leave a metal easilyleave a metal easily

Malleable and ductileMalleable and ductile-due to delocalized electrons not -due to delocalized electrons not belonging to any particular metal atom Therefore one belonging to any particular metal atom Therefore one layer of ions can slide over another without disrupting layer of ions can slide over another without disrupting the bond between metal atoms The electrons and the bond between metal atoms The electrons and metal ions simply rearrangemetal ions simply rearrange

HardnessHardness- tend to be hard due to tightly packed atoms- tend to be hard due to tightly packed atoms

Properties associated with Properties associated with bond typesbond types

Ionic bondingIonic bonding High melting pointsHigh melting points-due to strong electrostatic attraction -due to strong electrostatic attraction

between anions and cationsbetween anions and cations

Non-conductors of electricity in solid stateNon-conductors of electricity in solid state-due to -due to oppositely charged particles which are in fixed positionsoppositely charged particles which are in fixed positions

Conductors in the liquid (molten) stateConductors in the liquid (molten) state-due to the ions -due to the ions being able to move freely through the liquidbeing able to move freely through the liquid

HardnessHardness-due to strong electrostatic attraction between -due to strong electrostatic attraction between oppositely charged particlesoppositely charged particles

BrittleBrittle-due to the fixed location of oppositely charged -due to the fixed location of oppositely charged particles Displacement of ions moves them closer to ions particles Displacement of ions moves them closer to ions of a similar charge which increases the repulsive forces of a similar charge which increases the repulsive forces along the fracturealong the fracture

Properties associated with Properties associated with bond typesbond types

Covalent molecular bondingCovalent molecular bonding Low melting pointsLow melting points-due to generally weak -due to generally weak

attractive forces between molecules There attractive forces between molecules There are exceptions to this rule (eg Iare exceptions to this rule (eg I22 melts at melts at 11411400C but decomposes at 1000C but decomposes at 100000C) C)

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

SoftSoft-due to weak forces existing between -due to weak forces existing between moleculesmolecules

Properties associated with Properties associated with bond typesbond types

Covalent Network bondingCovalent Network bonding Very high melting points and boiling Very high melting points and boiling

pointspoints-due to strong covalent bonding -due to strong covalent bonding which form rigid 3-D structureswhich form rigid 3-D structures

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

Extremely hardExtremely hard- due to strong covalent - due to strong covalent bonding which form rigid 3-D structuresbonding which form rigid 3-D structures

The Chemical EarthThe Chemical Earth

Compiled by Robert Slider (2006)

Please share this resource with others

Properties of elements and Properties of elements and their compounds are very their compounds are very

differentdifferent8Fe(s) + S8Fe(s) + S88(s) + heat (s) + heat 8FeS(s) 8FeS(s)

substancsubstancee

colourcolour Melting Melting point point ((00C)C)

Boiling Boiling point point ((00C)C)

Density Density (gcm(gcm33))

magneticmagnetic

IronIron GreyGrey 15351535 27502750 7979 yesyes

SulphurSulphur YellowYellow 113113 445445 2121 nono

Iron (II) Iron (II) sulphidesulphide

Yellow-Yellow-goldgold

11941194 -- 484484 nono

Properties of elements Properties of elements compounds and mixtures compounds and mixtures

are very differentare very differentAluminiumAluminiumPhysical propertiesPhysical properties MP = 660MP = 66000CC Density = 27 gcmDensity = 27 gcm3 3

Conductivity = 378 x10Conductivity = 378 x1066 Smiddotm-1 Smiddotm-1 (20 degC)(20 degC)

Chemical propertiesChemical properties 4Al(s)+ 3O4Al(s)+ 3O22(g) (g) 2Al 2Al22OO33(s)(s) 2Al(s) + 6HCl(g) 2Al(s) + 6HCl(g) 2AlCl 2AlCl33(aq) (aq)

+ 3H+ 3H22(g)(g)

OxygenOxygenPhysical propertiesPhysical properties MP = -219MP = -21900CC Density = 00013 gcmDensity = 00013 gcm33

Conductivity = non-conductorConductivity = non-conductor

Bauxite ore Bauxite ore (Al(Al22OO33xHxH22O)O)Physical propertiesPhysical properties MP = 2045MP = 204500CC Density = 35-4 gcmDensity = 35-4 gcm33

Conductivity = non-conductorConductivity = non-conductor

Chemical propertiesChemical properties AlAl22OO33(s) + 2NaOH + 3H(s) + 2NaOH + 3H22O(l) O(l)

2Na[Al(OH)2Na[Al(OH)44](aq) (Bayer process)](aq) (Bayer process)

NB Bauxite is essentially an impure NB Bauxite is essentially an impure aluminium oxide The major aluminium oxide The major impurities include iron oxides impurities include iron oxides silicon dioxide and titanium silicon dioxide and titanium dioxide The impurities remain as dioxide The impurities remain as solids and do not react with solids and do not react with NaOH This process removes NaOH This process removes these impuritiesthese impurities

Structure of metalsStructure of metals

Metals can be described as three-Metals can be described as three-dimensional lattices of positive ions in a dimensional lattices of positive ions in a sea of delocalised electrons sea of delocalised electrons

Covalent BondingCovalent Bonding Covalent Molecular-strong Covalent Molecular-strong

bonds weak bonds weak intermolecular forces intermolecular forces holding molecules holding molecules togethertogether

Covalent Network-Covalent Network-covalent bonding lattice covalent bonding lattice that extends indefinitely that extends indefinitely throughout the crystalthroughout the crystal

Ionic bondingIonic bonding

No discreet molecules are formed in No discreet molecules are formed in ionic bonding due to electrostatic ionic bonding due to electrostatic forces holding the atoms together forces holding the atoms together They form a continuing 3D latticeThey form a continuing 3D lattice

-- --

-- -- --

--

-- --

---- --++

++

++

++++

++

++

++++++

Properties associated with Properties associated with bond typesbond types

Metallic bondingMetallic bonding High melting pointsHigh melting points-due to strong attraction between -due to strong attraction between

positively charged metal ions and delocalized positively charged metal ions and delocalized electrons The higher the valency the stronger the electrons The higher the valency the stronger the bond eg Cabond eg Ca2+2+ is stronger than K is stronger than K++

Good conductors of heat and electricityGood conductors of heat and electricity-due to the high -due to the high mobility of delocalized electrons Electrons enter and mobility of delocalized electrons Electrons enter and leave a metal easilyleave a metal easily

Malleable and ductileMalleable and ductile-due to delocalized electrons not -due to delocalized electrons not belonging to any particular metal atom Therefore one belonging to any particular metal atom Therefore one layer of ions can slide over another without disrupting layer of ions can slide over another without disrupting the bond between metal atoms The electrons and the bond between metal atoms The electrons and metal ions simply rearrangemetal ions simply rearrange

HardnessHardness- tend to be hard due to tightly packed atoms- tend to be hard due to tightly packed atoms

Properties associated with Properties associated with bond typesbond types

Ionic bondingIonic bonding High melting pointsHigh melting points-due to strong electrostatic attraction -due to strong electrostatic attraction

between anions and cationsbetween anions and cations

Non-conductors of electricity in solid stateNon-conductors of electricity in solid state-due to -due to oppositely charged particles which are in fixed positionsoppositely charged particles which are in fixed positions

Conductors in the liquid (molten) stateConductors in the liquid (molten) state-due to the ions -due to the ions being able to move freely through the liquidbeing able to move freely through the liquid

HardnessHardness-due to strong electrostatic attraction between -due to strong electrostatic attraction between oppositely charged particlesoppositely charged particles

BrittleBrittle-due to the fixed location of oppositely charged -due to the fixed location of oppositely charged particles Displacement of ions moves them closer to ions particles Displacement of ions moves them closer to ions of a similar charge which increases the repulsive forces of a similar charge which increases the repulsive forces along the fracturealong the fracture

Properties associated with Properties associated with bond typesbond types

Covalent molecular bondingCovalent molecular bonding Low melting pointsLow melting points-due to generally weak -due to generally weak

attractive forces between molecules There attractive forces between molecules There are exceptions to this rule (eg Iare exceptions to this rule (eg I22 melts at melts at 11411400C but decomposes at 1000C but decomposes at 100000C) C)

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

SoftSoft-due to weak forces existing between -due to weak forces existing between moleculesmolecules

Properties associated with Properties associated with bond typesbond types

Covalent Network bondingCovalent Network bonding Very high melting points and boiling Very high melting points and boiling

pointspoints-due to strong covalent bonding -due to strong covalent bonding which form rigid 3-D structureswhich form rigid 3-D structures

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

Extremely hardExtremely hard- due to strong covalent - due to strong covalent bonding which form rigid 3-D structuresbonding which form rigid 3-D structures

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Properties of elements Properties of elements compounds and mixtures compounds and mixtures

are very differentare very differentAluminiumAluminiumPhysical propertiesPhysical properties MP = 660MP = 66000CC Density = 27 gcmDensity = 27 gcm3 3

Conductivity = 378 x10Conductivity = 378 x1066 Smiddotm-1 Smiddotm-1 (20 degC)(20 degC)

Chemical propertiesChemical properties 4Al(s)+ 3O4Al(s)+ 3O22(g) (g) 2Al 2Al22OO33(s)(s) 2Al(s) + 6HCl(g) 2Al(s) + 6HCl(g) 2AlCl 2AlCl33(aq) (aq)

+ 3H+ 3H22(g)(g)

OxygenOxygenPhysical propertiesPhysical properties MP = -219MP = -21900CC Density = 00013 gcmDensity = 00013 gcm33

Conductivity = non-conductorConductivity = non-conductor

Bauxite ore Bauxite ore (Al(Al22OO33xHxH22O)O)Physical propertiesPhysical properties MP = 2045MP = 204500CC Density = 35-4 gcmDensity = 35-4 gcm33

Conductivity = non-conductorConductivity = non-conductor

Chemical propertiesChemical properties AlAl22OO33(s) + 2NaOH + 3H(s) + 2NaOH + 3H22O(l) O(l)

2Na[Al(OH)2Na[Al(OH)44](aq) (Bayer process)](aq) (Bayer process)

NB Bauxite is essentially an impure NB Bauxite is essentially an impure aluminium oxide The major aluminium oxide The major impurities include iron oxides impurities include iron oxides silicon dioxide and titanium silicon dioxide and titanium dioxide The impurities remain as dioxide The impurities remain as solids and do not react with solids and do not react with NaOH This process removes NaOH This process removes these impuritiesthese impurities

Structure of metalsStructure of metals

Metals can be described as three-Metals can be described as three-dimensional lattices of positive ions in a dimensional lattices of positive ions in a sea of delocalised electrons sea of delocalised electrons

Covalent BondingCovalent Bonding Covalent Molecular-strong Covalent Molecular-strong

bonds weak bonds weak intermolecular forces intermolecular forces holding molecules holding molecules togethertogether

Covalent Network-Covalent Network-covalent bonding lattice covalent bonding lattice that extends indefinitely that extends indefinitely throughout the crystalthroughout the crystal

Ionic bondingIonic bonding

No discreet molecules are formed in No discreet molecules are formed in ionic bonding due to electrostatic ionic bonding due to electrostatic forces holding the atoms together forces holding the atoms together They form a continuing 3D latticeThey form a continuing 3D lattice

-- --

-- -- --

--

-- --

---- --++

++

++

++++

++

++

++++++

Properties associated with Properties associated with bond typesbond types

Metallic bondingMetallic bonding High melting pointsHigh melting points-due to strong attraction between -due to strong attraction between

positively charged metal ions and delocalized positively charged metal ions and delocalized electrons The higher the valency the stronger the electrons The higher the valency the stronger the bond eg Cabond eg Ca2+2+ is stronger than K is stronger than K++

Good conductors of heat and electricityGood conductors of heat and electricity-due to the high -due to the high mobility of delocalized electrons Electrons enter and mobility of delocalized electrons Electrons enter and leave a metal easilyleave a metal easily

Malleable and ductileMalleable and ductile-due to delocalized electrons not -due to delocalized electrons not belonging to any particular metal atom Therefore one belonging to any particular metal atom Therefore one layer of ions can slide over another without disrupting layer of ions can slide over another without disrupting the bond between metal atoms The electrons and the bond between metal atoms The electrons and metal ions simply rearrangemetal ions simply rearrange

HardnessHardness- tend to be hard due to tightly packed atoms- tend to be hard due to tightly packed atoms

Properties associated with Properties associated with bond typesbond types

Ionic bondingIonic bonding High melting pointsHigh melting points-due to strong electrostatic attraction -due to strong electrostatic attraction

between anions and cationsbetween anions and cations

Non-conductors of electricity in solid stateNon-conductors of electricity in solid state-due to -due to oppositely charged particles which are in fixed positionsoppositely charged particles which are in fixed positions

Conductors in the liquid (molten) stateConductors in the liquid (molten) state-due to the ions -due to the ions being able to move freely through the liquidbeing able to move freely through the liquid

HardnessHardness-due to strong electrostatic attraction between -due to strong electrostatic attraction between oppositely charged particlesoppositely charged particles

BrittleBrittle-due to the fixed location of oppositely charged -due to the fixed location of oppositely charged particles Displacement of ions moves them closer to ions particles Displacement of ions moves them closer to ions of a similar charge which increases the repulsive forces of a similar charge which increases the repulsive forces along the fracturealong the fracture

Properties associated with Properties associated with bond typesbond types

Covalent molecular bondingCovalent molecular bonding Low melting pointsLow melting points-due to generally weak -due to generally weak

attractive forces between molecules There attractive forces between molecules There are exceptions to this rule (eg Iare exceptions to this rule (eg I22 melts at melts at 11411400C but decomposes at 1000C but decomposes at 100000C) C)

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

SoftSoft-due to weak forces existing between -due to weak forces existing between moleculesmolecules

Properties associated with Properties associated with bond typesbond types

Covalent Network bondingCovalent Network bonding Very high melting points and boiling Very high melting points and boiling

pointspoints-due to strong covalent bonding -due to strong covalent bonding which form rigid 3-D structureswhich form rigid 3-D structures

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

Extremely hardExtremely hard- due to strong covalent - due to strong covalent bonding which form rigid 3-D structuresbonding which form rigid 3-D structures

The Chemical EarthThe Chemical Earth

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Structure of metalsStructure of metals

Metals can be described as three-Metals can be described as three-dimensional lattices of positive ions in a dimensional lattices of positive ions in a sea of delocalised electrons sea of delocalised electrons

Covalent BondingCovalent Bonding Covalent Molecular-strong Covalent Molecular-strong

bonds weak bonds weak intermolecular forces intermolecular forces holding molecules holding molecules togethertogether

Covalent Network-Covalent Network-covalent bonding lattice covalent bonding lattice that extends indefinitely that extends indefinitely throughout the crystalthroughout the crystal

Ionic bondingIonic bonding

No discreet molecules are formed in No discreet molecules are formed in ionic bonding due to electrostatic ionic bonding due to electrostatic forces holding the atoms together forces holding the atoms together They form a continuing 3D latticeThey form a continuing 3D lattice

-- --

-- -- --

--

-- --

---- --++

++

++

++++

++

++

++++++

Properties associated with Properties associated with bond typesbond types

Metallic bondingMetallic bonding High melting pointsHigh melting points-due to strong attraction between -due to strong attraction between

positively charged metal ions and delocalized positively charged metal ions and delocalized electrons The higher the valency the stronger the electrons The higher the valency the stronger the bond eg Cabond eg Ca2+2+ is stronger than K is stronger than K++

Good conductors of heat and electricityGood conductors of heat and electricity-due to the high -due to the high mobility of delocalized electrons Electrons enter and mobility of delocalized electrons Electrons enter and leave a metal easilyleave a metal easily

Malleable and ductileMalleable and ductile-due to delocalized electrons not -due to delocalized electrons not belonging to any particular metal atom Therefore one belonging to any particular metal atom Therefore one layer of ions can slide over another without disrupting layer of ions can slide over another without disrupting the bond between metal atoms The electrons and the bond between metal atoms The electrons and metal ions simply rearrangemetal ions simply rearrange

HardnessHardness- tend to be hard due to tightly packed atoms- tend to be hard due to tightly packed atoms

Properties associated with Properties associated with bond typesbond types

Ionic bondingIonic bonding High melting pointsHigh melting points-due to strong electrostatic attraction -due to strong electrostatic attraction

between anions and cationsbetween anions and cations

Non-conductors of electricity in solid stateNon-conductors of electricity in solid state-due to -due to oppositely charged particles which are in fixed positionsoppositely charged particles which are in fixed positions

Conductors in the liquid (molten) stateConductors in the liquid (molten) state-due to the ions -due to the ions being able to move freely through the liquidbeing able to move freely through the liquid

HardnessHardness-due to strong electrostatic attraction between -due to strong electrostatic attraction between oppositely charged particlesoppositely charged particles

BrittleBrittle-due to the fixed location of oppositely charged -due to the fixed location of oppositely charged particles Displacement of ions moves them closer to ions particles Displacement of ions moves them closer to ions of a similar charge which increases the repulsive forces of a similar charge which increases the repulsive forces along the fracturealong the fracture

Properties associated with Properties associated with bond typesbond types

Covalent molecular bondingCovalent molecular bonding Low melting pointsLow melting points-due to generally weak -due to generally weak

attractive forces between molecules There attractive forces between molecules There are exceptions to this rule (eg Iare exceptions to this rule (eg I22 melts at melts at 11411400C but decomposes at 1000C but decomposes at 100000C) C)

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

SoftSoft-due to weak forces existing between -due to weak forces existing between moleculesmolecules

Properties associated with Properties associated with bond typesbond types

Covalent Network bondingCovalent Network bonding Very high melting points and boiling Very high melting points and boiling

pointspoints-due to strong covalent bonding -due to strong covalent bonding which form rigid 3-D structureswhich form rigid 3-D structures

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

Extremely hardExtremely hard- due to strong covalent - due to strong covalent bonding which form rigid 3-D structuresbonding which form rigid 3-D structures

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Covalent BondingCovalent Bonding Covalent Molecular-strong Covalent Molecular-strong

bonds weak bonds weak intermolecular forces intermolecular forces holding molecules holding molecules togethertogether

Covalent Network-Covalent Network-covalent bonding lattice covalent bonding lattice that extends indefinitely that extends indefinitely throughout the crystalthroughout the crystal

Ionic bondingIonic bonding

No discreet molecules are formed in No discreet molecules are formed in ionic bonding due to electrostatic ionic bonding due to electrostatic forces holding the atoms together forces holding the atoms together They form a continuing 3D latticeThey form a continuing 3D lattice

-- --

-- -- --

--

-- --

---- --++

++

++

++++

++

++

++++++

Properties associated with Properties associated with bond typesbond types

Metallic bondingMetallic bonding High melting pointsHigh melting points-due to strong attraction between -due to strong attraction between

positively charged metal ions and delocalized positively charged metal ions and delocalized electrons The higher the valency the stronger the electrons The higher the valency the stronger the bond eg Cabond eg Ca2+2+ is stronger than K is stronger than K++

Good conductors of heat and electricityGood conductors of heat and electricity-due to the high -due to the high mobility of delocalized electrons Electrons enter and mobility of delocalized electrons Electrons enter and leave a metal easilyleave a metal easily

Malleable and ductileMalleable and ductile-due to delocalized electrons not -due to delocalized electrons not belonging to any particular metal atom Therefore one belonging to any particular metal atom Therefore one layer of ions can slide over another without disrupting layer of ions can slide over another without disrupting the bond between metal atoms The electrons and the bond between metal atoms The electrons and metal ions simply rearrangemetal ions simply rearrange

HardnessHardness- tend to be hard due to tightly packed atoms- tend to be hard due to tightly packed atoms

Properties associated with Properties associated with bond typesbond types

Ionic bondingIonic bonding High melting pointsHigh melting points-due to strong electrostatic attraction -due to strong electrostatic attraction

between anions and cationsbetween anions and cations

Non-conductors of electricity in solid stateNon-conductors of electricity in solid state-due to -due to oppositely charged particles which are in fixed positionsoppositely charged particles which are in fixed positions

Conductors in the liquid (molten) stateConductors in the liquid (molten) state-due to the ions -due to the ions being able to move freely through the liquidbeing able to move freely through the liquid

HardnessHardness-due to strong electrostatic attraction between -due to strong electrostatic attraction between oppositely charged particlesoppositely charged particles

BrittleBrittle-due to the fixed location of oppositely charged -due to the fixed location of oppositely charged particles Displacement of ions moves them closer to ions particles Displacement of ions moves them closer to ions of a similar charge which increases the repulsive forces of a similar charge which increases the repulsive forces along the fracturealong the fracture

Properties associated with Properties associated with bond typesbond types

Covalent molecular bondingCovalent molecular bonding Low melting pointsLow melting points-due to generally weak -due to generally weak

attractive forces between molecules There attractive forces between molecules There are exceptions to this rule (eg Iare exceptions to this rule (eg I22 melts at melts at 11411400C but decomposes at 1000C but decomposes at 100000C) C)

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

SoftSoft-due to weak forces existing between -due to weak forces existing between moleculesmolecules

Properties associated with Properties associated with bond typesbond types

Covalent Network bondingCovalent Network bonding Very high melting points and boiling Very high melting points and boiling

pointspoints-due to strong covalent bonding -due to strong covalent bonding which form rigid 3-D structureswhich form rigid 3-D structures

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

Extremely hardExtremely hard- due to strong covalent - due to strong covalent bonding which form rigid 3-D structuresbonding which form rigid 3-D structures

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Ionic bondingIonic bonding

No discreet molecules are formed in No discreet molecules are formed in ionic bonding due to electrostatic ionic bonding due to electrostatic forces holding the atoms together forces holding the atoms together They form a continuing 3D latticeThey form a continuing 3D lattice

-- --

-- -- --

--

-- --

---- --++

++

++

++++

++

++

++++++

Properties associated with Properties associated with bond typesbond types

Metallic bondingMetallic bonding High melting pointsHigh melting points-due to strong attraction between -due to strong attraction between

positively charged metal ions and delocalized positively charged metal ions and delocalized electrons The higher the valency the stronger the electrons The higher the valency the stronger the bond eg Cabond eg Ca2+2+ is stronger than K is stronger than K++

Good conductors of heat and electricityGood conductors of heat and electricity-due to the high -due to the high mobility of delocalized electrons Electrons enter and mobility of delocalized electrons Electrons enter and leave a metal easilyleave a metal easily

Malleable and ductileMalleable and ductile-due to delocalized electrons not -due to delocalized electrons not belonging to any particular metal atom Therefore one belonging to any particular metal atom Therefore one layer of ions can slide over another without disrupting layer of ions can slide over another without disrupting the bond between metal atoms The electrons and the bond between metal atoms The electrons and metal ions simply rearrangemetal ions simply rearrange

HardnessHardness- tend to be hard due to tightly packed atoms- tend to be hard due to tightly packed atoms

Properties associated with Properties associated with bond typesbond types

Ionic bondingIonic bonding High melting pointsHigh melting points-due to strong electrostatic attraction -due to strong electrostatic attraction

between anions and cationsbetween anions and cations

Non-conductors of electricity in solid stateNon-conductors of electricity in solid state-due to -due to oppositely charged particles which are in fixed positionsoppositely charged particles which are in fixed positions

Conductors in the liquid (molten) stateConductors in the liquid (molten) state-due to the ions -due to the ions being able to move freely through the liquidbeing able to move freely through the liquid

HardnessHardness-due to strong electrostatic attraction between -due to strong electrostatic attraction between oppositely charged particlesoppositely charged particles

BrittleBrittle-due to the fixed location of oppositely charged -due to the fixed location of oppositely charged particles Displacement of ions moves them closer to ions particles Displacement of ions moves them closer to ions of a similar charge which increases the repulsive forces of a similar charge which increases the repulsive forces along the fracturealong the fracture

Properties associated with Properties associated with bond typesbond types

Covalent molecular bondingCovalent molecular bonding Low melting pointsLow melting points-due to generally weak -due to generally weak

attractive forces between molecules There attractive forces between molecules There are exceptions to this rule (eg Iare exceptions to this rule (eg I22 melts at melts at 11411400C but decomposes at 1000C but decomposes at 100000C) C)

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

SoftSoft-due to weak forces existing between -due to weak forces existing between moleculesmolecules

Properties associated with Properties associated with bond typesbond types

Covalent Network bondingCovalent Network bonding Very high melting points and boiling Very high melting points and boiling

pointspoints-due to strong covalent bonding -due to strong covalent bonding which form rigid 3-D structureswhich form rigid 3-D structures

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

Extremely hardExtremely hard- due to strong covalent - due to strong covalent bonding which form rigid 3-D structuresbonding which form rigid 3-D structures

The Chemical EarthThe Chemical Earth

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Properties associated with Properties associated with bond typesbond types

Metallic bondingMetallic bonding High melting pointsHigh melting points-due to strong attraction between -due to strong attraction between

positively charged metal ions and delocalized positively charged metal ions and delocalized electrons The higher the valency the stronger the electrons The higher the valency the stronger the bond eg Cabond eg Ca2+2+ is stronger than K is stronger than K++

Good conductors of heat and electricityGood conductors of heat and electricity-due to the high -due to the high mobility of delocalized electrons Electrons enter and mobility of delocalized electrons Electrons enter and leave a metal easilyleave a metal easily

Malleable and ductileMalleable and ductile-due to delocalized electrons not -due to delocalized electrons not belonging to any particular metal atom Therefore one belonging to any particular metal atom Therefore one layer of ions can slide over another without disrupting layer of ions can slide over another without disrupting the bond between metal atoms The electrons and the bond between metal atoms The electrons and metal ions simply rearrangemetal ions simply rearrange

HardnessHardness- tend to be hard due to tightly packed atoms- tend to be hard due to tightly packed atoms

Properties associated with Properties associated with bond typesbond types

Ionic bondingIonic bonding High melting pointsHigh melting points-due to strong electrostatic attraction -due to strong electrostatic attraction

between anions and cationsbetween anions and cations

Non-conductors of electricity in solid stateNon-conductors of electricity in solid state-due to -due to oppositely charged particles which are in fixed positionsoppositely charged particles which are in fixed positions

Conductors in the liquid (molten) stateConductors in the liquid (molten) state-due to the ions -due to the ions being able to move freely through the liquidbeing able to move freely through the liquid

HardnessHardness-due to strong electrostatic attraction between -due to strong electrostatic attraction between oppositely charged particlesoppositely charged particles

BrittleBrittle-due to the fixed location of oppositely charged -due to the fixed location of oppositely charged particles Displacement of ions moves them closer to ions particles Displacement of ions moves them closer to ions of a similar charge which increases the repulsive forces of a similar charge which increases the repulsive forces along the fracturealong the fracture

Properties associated with Properties associated with bond typesbond types

Covalent molecular bondingCovalent molecular bonding Low melting pointsLow melting points-due to generally weak -due to generally weak

attractive forces between molecules There attractive forces between molecules There are exceptions to this rule (eg Iare exceptions to this rule (eg I22 melts at melts at 11411400C but decomposes at 1000C but decomposes at 100000C) C)

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

SoftSoft-due to weak forces existing between -due to weak forces existing between moleculesmolecules

Properties associated with Properties associated with bond typesbond types

Covalent Network bondingCovalent Network bonding Very high melting points and boiling Very high melting points and boiling

pointspoints-due to strong covalent bonding -due to strong covalent bonding which form rigid 3-D structureswhich form rigid 3-D structures

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

Extremely hardExtremely hard- due to strong covalent - due to strong covalent bonding which form rigid 3-D structuresbonding which form rigid 3-D structures

The Chemical EarthThe Chemical Earth

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Please share this resource with others

Properties associated with Properties associated with bond typesbond types

Ionic bondingIonic bonding High melting pointsHigh melting points-due to strong electrostatic attraction -due to strong electrostatic attraction

between anions and cationsbetween anions and cations

Non-conductors of electricity in solid stateNon-conductors of electricity in solid state-due to -due to oppositely charged particles which are in fixed positionsoppositely charged particles which are in fixed positions

Conductors in the liquid (molten) stateConductors in the liquid (molten) state-due to the ions -due to the ions being able to move freely through the liquidbeing able to move freely through the liquid

HardnessHardness-due to strong electrostatic attraction between -due to strong electrostatic attraction between oppositely charged particlesoppositely charged particles

BrittleBrittle-due to the fixed location of oppositely charged -due to the fixed location of oppositely charged particles Displacement of ions moves them closer to ions particles Displacement of ions moves them closer to ions of a similar charge which increases the repulsive forces of a similar charge which increases the repulsive forces along the fracturealong the fracture

Properties associated with Properties associated with bond typesbond types

Covalent molecular bondingCovalent molecular bonding Low melting pointsLow melting points-due to generally weak -due to generally weak

attractive forces between molecules There attractive forces between molecules There are exceptions to this rule (eg Iare exceptions to this rule (eg I22 melts at melts at 11411400C but decomposes at 1000C but decomposes at 100000C) C)

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

SoftSoft-due to weak forces existing between -due to weak forces existing between moleculesmolecules

Properties associated with Properties associated with bond typesbond types

Covalent Network bondingCovalent Network bonding Very high melting points and boiling Very high melting points and boiling

pointspoints-due to strong covalent bonding -due to strong covalent bonding which form rigid 3-D structureswhich form rigid 3-D structures

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

Extremely hardExtremely hard- due to strong covalent - due to strong covalent bonding which form rigid 3-D structuresbonding which form rigid 3-D structures

The Chemical EarthThe Chemical Earth

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Please share this resource with others

Properties associated with Properties associated with bond typesbond types

Covalent molecular bondingCovalent molecular bonding Low melting pointsLow melting points-due to generally weak -due to generally weak

attractive forces between molecules There attractive forces between molecules There are exceptions to this rule (eg Iare exceptions to this rule (eg I22 melts at melts at 11411400C but decomposes at 1000C but decomposes at 100000C) C)

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

SoftSoft-due to weak forces existing between -due to weak forces existing between moleculesmolecules

Properties associated with Properties associated with bond typesbond types

Covalent Network bondingCovalent Network bonding Very high melting points and boiling Very high melting points and boiling

pointspoints-due to strong covalent bonding -due to strong covalent bonding which form rigid 3-D structureswhich form rigid 3-D structures

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

Extremely hardExtremely hard- due to strong covalent - due to strong covalent bonding which form rigid 3-D structuresbonding which form rigid 3-D structures

The Chemical EarthThe Chemical Earth

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Please share this resource with others

Properties associated with Properties associated with bond typesbond types

Covalent Network bondingCovalent Network bonding Very high melting points and boiling Very high melting points and boiling

pointspoints-due to strong covalent bonding -due to strong covalent bonding which form rigid 3-D structureswhich form rigid 3-D structures

Non-conductorsNon-conductors-due to lack of mobile -due to lack of mobile charged species or delocalized electronscharged species or delocalized electrons

Extremely hardExtremely hard- due to strong covalent - due to strong covalent bonding which form rigid 3-D structuresbonding which form rigid 3-D structures

The Chemical EarthThe Chemical Earth

Compiled by Robert Slider (2006)

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The Chemical EarthThe Chemical Earth

Compiled by Robert Slider (2006)

Please share this resource with others