Chemistry:Chemistry:

THE STUDY OF MATTERTHE STUDY OF MATTER

So what is matter?So what is matter?

MatterMatter

Must have Must have massmass

It is different from weight…..Why?It is different from weight…..Why?

Must occupy space (have Must occupy space (have volumevolume))

Matter Has DensityMatter Has Density

DensityDensity of a Substance of a Substance = = MassMass

VolumeVolumeSee Reference Table S to compare density of elementsSee Reference Table S to compare density of elements

States of MatterStates of Matter Matter can exist in three basic states:Matter can exist in three basic states:

Solid (s), Liquid (l), Gas (g)Solid (s), Liquid (l), Gas (g)

How are these states different from each other?How are these states different from each other?

Can Matter be Destroyed?Can Matter be Destroyed?

Example:Example:

When 400 grams of wood When 400 grams of wood are burned only about 30 are burned only about 30 grams of ash remain. grams of ash remain.

What would you think?What would you think?

What happened to the What happened to the missing matter?missing matter?

Law of Conservation of MatterLaw of Conservation of Matter

Matter cannot be Matter cannot be created or destroyedcreated or destroyed

Matter isn’t being lost but changing in form!

Atoms are all still Atoms are all still there they just get there they just get rearrangedrearranged

Balanced chemical equations show the Balanced chemical equations show the number of atoms stay the same during number of atoms stay the same during reactions and thus obey this law.reactions and thus obey this law.

Basic Types of Matter:Basic Types of Matter: Elements vs. Compounds Elements vs. Compounds

ElementsElements

• Made of atoms of one specific typeMade of atoms of one specific type

• Cannot be broken down chemicallyCannot be broken down chemically

• Have specific properties.Have specific properties.

Examples of ElementsExamples of Elements

Where Do We Get Elements?Where Do We Get Elements?

Obtained in Obtained in nature in their nature in their pure state.pure state.

Found combined Found combined with other elements with other elements in compounds in compounds

Man-made through Man-made through nuclear bombardment nuclear bombardment reactionsreactions

Elements and Their SymbolsElements and Their Symbols Take Note Please!Take Note Please!

Elements have either one Elements have either one or two letters when they or two letters when they are written as a symbol.are written as a symbol.

If two letters, the second If two letters, the second letter is written lower letter is written lower case. (Ex: Write Cu for case. (Ex: Write Cu for copper not CU)copper not CU)

Why is this so important?Why is this so important?

Usually it is pretty easy to match an Usually it is pretty easy to match an element to its symbol (Ex: Neon = Ne)element to its symbol (Ex: Neon = Ne)

Sometimes the symbol is derived from a Sometimes the symbol is derived from a Latin name for the element.Latin name for the element.Ex: Au = gold (comes from Latin word aurum)Ex: Au = gold (comes from Latin word aurum)

Tricky ElementsTricky Elements Na = sodiumNa = sodium K = potassiumK = potassium Fe = ironFe = iron Cu = copper Cu = copper Sb = antimonySb = antimony Sn = tinSn = tin Pb = leadPb = lead Hg = mercuryHg = mercury W = tungstunW = tungstun Au = goldAu = gold Ag = silverAg = silver

Phases and ElementsPhases and Elements Solids: Solids:

Most elements are solidsMost elements are solids

Gases: Gases: H, He, Ne, Ar, Kr, Xe, Rn, H, He, Ne, Ar, Kr, Xe, Rn,

N, O, F, ClN, O, F, Cl

Liquids:Liquids: Hg, BrHg, Br

Let’s make a note of these on our Let’s make a note of these on our Periodic Tables!Periodic Tables!

Diatomic ElementsDiatomic Elements Most elements are Most elements are

monoatomic in pure form.monoatomic in pure form.

Some elements have two Some elements have two atoms joined (diatomic)atoms joined (diatomic)

Who are they?Who are they? Remember Remember BrINClHOFBrINClHOF

Let’s make a note of these on Let’s make a note of these on our Periodic Tables!our Periodic Tables!

CompoundsCompounds

Two or more different elements bonded Two or more different elements bonded together together chemicallychemically

Ex: CEx: C66HH1212OO66, NO, NO22, CO, CO22, NaCl, NaCl

Note: Most elements in nature do not exist in Note: Most elements in nature do not exist in their pure state, but in compounds.their pure state, but in compounds.

Why?Why?

Law of Definite ProportionsLaw of Definite Proportions

• CompoundsCompounds have specific have specific formulas that show the formulas that show the proportion of elements to proportion of elements to each other. each other.

• Ex: Water is always HEx: Water is always H22OO

• A “mixture” has proportions A “mixture” has proportions that can varythat can vary

• Ex: salt water Ex: salt water

Getting New PropertiesGetting New Properties

Compounds have different chemical and Compounds have different chemical and physical properties than the elements that physical properties than the elements that make them up.make them up.

- - SodiumSodium (Na) (Na)

Toxic metalToxic metal

- - ChlorineChlorine (Cl) (Cl)

Toxic gasToxic gas

Sodium ChlorideSodium Chloride (NaCl) (NaCl)

White edible crystalWhite edible crystal

salt for my french fries!!salt for my french fries!!

Focus QuestionFocus Question

What makes atoms of one element What makes atoms of one element different from another?different from another?

What is inside its atoms…What is inside its atoms…

http://www.pbslearningmedia.org/asset/lsps07_int_theatom/

Atomic BasicsAtomic Basics

Atoms consist of three basic parts.Atoms consist of three basic parts.

ProtonsProtonsNeutronsNeutronsElectronsElectrons

Fill in Chart:Fill in Chart:

Particle Charge Mass Location Symbol

Proton

Neutron

Electron

Atomic Number: Atomic Number: Tells us the number of Tells us the number of

protons in nucleusprotons in nucleus It is unique for each It is unique for each

elementelement

Atomic ChargeAtomic Charge

Atoms are neutral particlesAtoms are neutral particles

Number of electrons (-) = number of protons Number of electrons (-) = number of protons (+)(+)

How many electrons does an How many electrons does an atomatom of carbon of carbon have?have?

Nuclear ChargeNuclear Charge

Nuclear ChargeNuclear Charge: : the charge on the nucleus of the atom.the charge on the nucleus of the atom.(+) positive charge = to number of protons(+) positive charge = to number of protons

What is the Nuclear Charge?

What is the Atomic Number?

What is this Element?

Ionic ChargeIonic Charge

Ions:Ions: atoms with a charge atoms with a charge

Protons don’t equal electrons!!Protons don’t equal electrons!!Atom has Atom has gained or lost electronsgained or lost electrons

Gain electrons: become (-) ionGain electrons: become (-) ionLose electrons: become (+) ionLose electrons: become (+) ion

P = 9P = 9E = 10E = 10What is the element? What is it’s ionic charge?What is the element? What is it’s ionic charge?

Ionic Charge PracticeIonic Charge Practice

Try a few for practice…Try a few for practice…

Finding the Atom’s Finding the Atom’s MassMass

Mass Number:Mass Number: Sum of the number of protons + neutronsSum of the number of protons + neutrons Each has a mass of 1 amu. (atomic mass unit)Each has a mass of 1 amu. (atomic mass unit)

Ex: Ex: P = 23P = 23 N = 21N = 21

What is the Atomic Mass Number?What is the Atomic Mass Number?

What is this element?What is this element?

IsotopesIsotopes

Isotopes:Isotopes: atoms of the same element with atoms of the same element with different atomic mass.different atomic mass.

Same # protonsSame # protonsDifferent # neutronsDifferent # neutrons

Ex: Carbon-12, Carbon-13, Carbon-14Ex: Carbon-12, Carbon-13, Carbon-14How many protons?How many protons?How many neutrons?How many neutrons?

Average Atomic Mass:Average Atomic Mass:

Atomic mass you see on periodic tableAtomic mass you see on periodic table

Represents the average mass of all the Represents the average mass of all the isotopes of an element in a typical sample.isotopes of an element in a typical sample.

Based upon abundance of each isotope and Based upon abundance of each isotope and their masstheir mass

Calculating Average Atomic MassCalculating Average Atomic Mass

Mass of each isotope x abundance Mass of each isotope x abundance (change % abundance to decimal)(change % abundance to decimal)

Add together answersAdd together answers

Ex: ChlorineEx: Chlorine

Crash Course: Atomic BasicsCrash Course: Atomic Basicshttps://www.youtube.com/watch?v=FSyAe

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