24.224.2

The p-block elements: metals and The p-block elements: metals and nonmetalsnonmetals

Group 3AGroup 3A

Boron- occurs naturally in borate minerals ( found Boron- occurs naturally in borate minerals ( found in desert U.S.)in desert U.S.)

Purified borax – sodium tetraborate decahydrate Purified borax – sodium tetraborate decahydrate (Na(Na22BB44OO77

..10H10H22O) is soft colorless and crystalline; O) is soft colorless and crystalline; found in glass, ceramics and fertilizers; used to found in glass, ceramics and fertilizers; used to soften water, disinfect, or as fluxsoften water, disinfect, or as flux

Pure Boron- black, hard, lustrous, but brittle- it is Pure Boron- black, hard, lustrous, but brittle- it is a metalloid, semiconductora metalloid, semiconductor

prepared by: Bprepared by: B22OO33 +3Mg ----2B + 3MgO +3Mg ----2B + 3MgO

Boron carbide- BBoron carbide- B44C very hard, used in making C very hard, used in making machine toolsmachine tools

Aluminum- most abundant metal in crust; is not Aluminum- most abundant metal in crust; is not found in pure form in crust- bauxite(Alfound in pure form in crust- bauxite(Al22OO3) 3) and and corundum (impure Alcorundum (impure Al22OO33) are common minerals) are common minerals

Valuable properties: strength, ductility, low Valuable properties: strength, ductility, low density, corrosion resistance, high electrical density, corrosion resistance, high electrical conductivity, forms resistant oxide coating- conductivity, forms resistant oxide coating- used for structures and manufacturing used for structures and manufacturing

Aluminum and Group 3AAluminum and Group 3A

After discovery of an inexpensive way to After discovery of an inexpensive way to produce pure Al, use of Al exploded ( it produce pure Al, use of Al exploded ( it was much cheaper now)-in aircraft, was much cheaper now)-in aircraft, cookware, cans, foil etc.cookware, cans, foil etc.

Other Group 3A elements are rare- Other Group 3A elements are rare- gallium used in thermometers and as gallium used in thermometers and as semiconductorsemiconductor

Aluminum and Group 3AAluminum and Group 3A

Carbon and Group 4ACarbon and Group 4A

C- fundamental element in natural worldC- fundamental element in natural world C- has allotropes- diamond and graphite and C- has allotropes- diamond and graphite and

few more ( bucky balls, nanotubes)few more ( bucky balls, nanotubes) C- nonmetalC- nonmetal Si- Si fundamental element in geological world- Si- Si fundamental element in geological world-

SiOSiO22 ( silicon dioxide) is quartz ( silicon dioxide) is quartz Si and Ge are semi-conductors (metalloids) ; Si and Ge are semi-conductors (metalloids) ;

good insulators but at hi T they conduct good insulators but at hi T they conduct electricity- used in transistors and photocellselectricity- used in transistors and photocells

GraphiteGraphite

Sheets of benzene rings.

Sheets can slip over each other- good lubricant

DiamondDiamond

Tetrahedralarray ofcarbon

Very hard

SphericalSpherical

A regular structure of5 and 6 memberrings.

Fullerenes orBuckyballs.C60

Sn and Pb are metals, fairly unreactiveSn and Pb are metals, fairly unreactive Sn- found as SnOSn- found as SnO22 in nature- malleable, used in nature- malleable, used

in alloys ( bronze is Sn and Cu) and solder (Sn in alloys ( bronze is Sn and Cu) and solder (Sn and Pb); SnFand Pb); SnF22- stannous fluoride is used in - stannous fluoride is used in toothpastetoothpaste

Pb- low m. pt. ; refined from mineral galena Pb- low m. pt. ; refined from mineral galena (PbS); used in plumbing and lead storage (PbS); used in plumbing and lead storage batteriesbatteries

Pb has health concerns- no more leaded Pb has health concerns- no more leaded gasoline or lead-based paintsgasoline or lead-based paints

Carbon and Group 4ACarbon and Group 4A

Nitrogen and Group 5Nitrogen and Group 5

N is a nonmetal, gas at rm temp; essential for N is a nonmetal, gas at rm temp; essential for living thingsliving things

80% of air is N80% of air is N22, but most living things cannot , but most living things cannot use pure nitrogen- bacteria “fix” nitrogen into use pure nitrogen- bacteria “fix” nitrogen into usable formusable form

NN22 is commercially obtained 2 ways, both from is commercially obtained 2 ways, both from air: 1) fractional distillation ( nitrogen boils off air: 1) fractional distillation ( nitrogen boils off first)first)

2) Air is moved over hot coke ( C) and 2) Air is moved over hot coke ( C) and oxygen is removed and forms COoxygen is removed and forms CO22leaving leaving nitrogennitrogen

NN22 is colorless, odorless, tasteless, slightly is colorless, odorless, tasteless, slightly soluble in water soluble in water

Used to make NHUsed to make NH33, ammonia in Haber process , ammonia in Haber process (pg 715), and nitric acid(pg 715), and nitric acid

Ammonia- strong odor, colorless gas, soluble Ammonia- strong odor, colorless gas, soluble in water, slightly basic; used in cleaning in water, slightly basic; used in cleaning products, fertilizers, refrigerantproducts, fertilizers, refrigerant

Nitric acid ( can be made from ammonia)-used Nitric acid ( can be made from ammonia)-used in etching, fertilizers, dyes and explosivesin etching, fertilizers, dyes and explosives

Nitrogen and Group 5Nitrogen and Group 5

P- nonmetal; important in living things (DNA, P- nonmetal; important in living things (DNA, bones, teeth, ATP)bones, teeth, ATP)

Found as phosphate rockFound as phosphate rock In pure form- 2 types of P- red and whiteIn pure form- 2 types of P- red and white white is very reactive and stored under water; white is very reactive and stored under water;

red is less reactive-used in matchesred is less reactive-used in matches Arsenic, Bi and antimony occur in nature as Arsenic, Bi and antimony occur in nature as

sulfide mineralssulfide minerals Sb and Bi expand when heated- used in alloys Sb and Bi expand when heated- used in alloys

( printing presses)( printing presses)

Nitrogen and Group 5Nitrogen and Group 5

Oxygen and Group 6AOxygen and Group 6A

O and S nonmetals; Se and Te are O and S nonmetals; Se and Te are metalloids; Po is a radioactive, metal that metalloids; Po is a radioactive, metal that occurs in small amountsoccurs in small amounts

OxygenOxygen There are more oxygen atoms in the Earth’s crust, There are more oxygen atoms in the Earth’s crust,

surface waters and atmosphere than atoms of any surface waters and atmosphere than atoms of any other element.other element.

Molecular oxygen makes up 23% by mass of the Molecular oxygen makes up 23% by mass of the atmosphere.atmosphere.

Oxygen in compounds make up 46% by mass of the Oxygen in compounds make up 46% by mass of the crust and upper mantle.crust and upper mantle.

In surface waters, oxygen accounts for 86% by mass.In surface waters, oxygen accounts for 86% by mass.

Oxygen productionOxygen production

Industrially, oxygen is obtained by liquefying and Industrially, oxygen is obtained by liquefying and fractionally distilling air.fractionally distilling air.

Worldwide production of oxygen is almost 2 x 10Worldwide production of oxygen is almost 2 x 101111 pounds each year. This is only 10pounds each year. This is only 10-5-5% of the oxygen % of the oxygen in the atmosphere.in the atmosphere.

Molecular oxygen is continuously being made via Molecular oxygen is continuously being made via photosynthesis by plants that require carbon dioxide.photosynthesis by plants that require carbon dioxide.

Animals breathe in oxygen and breathe out carbon Animals breathe in oxygen and breathe out carbon dioxide.dioxide.

Oxygen useOxygen use The major industrial use is in the production The major industrial use is in the production

of steel. This accounts for 65-85% of of steel. This accounts for 65-85% of production.production.

Large quantities of oxygen are also used to Large quantities of oxygen are also used to produce titanium(IV) oxide, a white pigment.produce titanium(IV) oxide, a white pigment.

Oxygen is also used as an oxidizing agent to Oxygen is also used as an oxidizing agent to power the space shuttle, for sewage power the space shuttle, for sewage treatment and various industrial processes.treatment and various industrial processes.

It also is used in medicine. It also is used in medicine.

Physical properties of OPhysical properties of O22

OO22 is a colorless, odorless, tasteless gas. is a colorless, odorless, tasteless gas.

Solubility.Solubility.

Only slightly soluble in water.Only slightly soluble in water.

Less soluble in salt water than fresh water.Less soluble in salt water than fresh water.

Increasing temperature will decrease solubility Increasing temperature will decrease solubility in water.in water.

It is paramagnetic (weakly magnetic)It is paramagnetic (weakly magnetic)

OzoneOzone

Ozone, OOzone, O33, is an allotrope of molecular , is an allotrope of molecular

oxygen.oxygen. It is prepared by electrical discharge or UV It is prepared by electrical discharge or UV

light on molecular oxygen.light on molecular oxygen.

3O3O22 (g) (g) 2O 2O2 2 (g)(g)

Ozone is a diamagnetic blue gas with a Ozone is a diamagnetic blue gas with a characteristic odor. Concentrations as low characteristic odor. Concentrations as low as 0.01 ppm can be detected by odor.as 0.01 ppm can be detected by odor.

UV or silent electrical discharge

OzoneOzone Ozone is unstable and very reactive, Ozone is unstable and very reactive,

Catalysts and UV light cause it to decompose.Catalysts and UV light cause it to decompose.

2O2O33 (g) (g) 3O 3O22 (g) (g)

It is also a more powerful oxidizing agent that It is also a more powerful oxidizing agent that molecular oxygen. In acidic solutions, it is one of molecular oxygen. In acidic solutions, it is one of the most powerful oxidizing agents known.the most powerful oxidizing agents known.OO33 (g) (g) + 2H + 2H++ + 2e + 2e-- O O22 (g) (g) + H + H22OO (l) (l) E Eoo = +2.07 V = +2.07 V

catalyst or UV

OzoneOzone Atmospheric ozone.Atmospheric ozone.

Ozone strongly absorbs UV radiation in Ozone strongly absorbs UV radiation in the 220-290 nm range.the 220-290 nm range.

The ozone layer is stratospheric-level OThe ozone layer is stratospheric-level O33. .

It protects the Earth’s surface from the It protects the Earth’s surface from the Sun’s intense UV radiation.Sun’s intense UV radiation.

Tropospheric level OTropospheric level O33, however, is , however, is

harmful. It contributes to smog formation harmful. It contributes to smog formation and causes rubber to crack.and causes rubber to crack.

OzoneOzone Ozone as a disinfectant.Ozone as a disinfectant. OO33 is now being used in hospitals, hotels and is now being used in hospitals, hotels and

commercial laundries.commercial laundries. It is also used to purify drinking water.It is also used to purify drinking water.

AdvantageAdvantage After reaction, only OAfter reaction, only O22 remains unlike when Cl remains unlike when Cl22 is is

used. Chlorine can form chlorocarbons.used. Chlorine can form chlorocarbons.

DisadvantageDisadvantage No residual protection. Since it rapidly No residual protection. Since it rapidly

decomposes, there is no protection after water decomposes, there is no protection after water treatment.treatment.

Chemical Properties of OChemical Properties of O

When substances combine w/oxygen the When substances combine w/oxygen the process is called oxidation, mostly the products process is called oxidation, mostly the products are oxidesare oxides

Usually this occurs when you heat the Usually this occurs when you heat the elements in the presence of oxygenelements in the presence of oxygen

Oxides of metals are usually solids, and can Oxides of metals are usually solids, and can form a basic water solutionform a basic water solution

Oxides of nonmetals can be a solid, liquid or Oxides of nonmetals can be a solid, liquid or gas and tend to form acidic water solutionsgas and tend to form acidic water solutions

SulfurSulfur S is a yellow, tasteless, odorless, brittle solidS is a yellow, tasteless, odorless, brittle solid Elemental sulfur has more allotropes than any other elements.Elemental sulfur has more allotropes than any other elements.

The S-S bond isthe third strongestsingle bond betweenthe same kind ofatoms.

At room temperature,the most commonform is rhombic,consisting of eight member rings.(S8)

SulfurSulfur When sulfur is heated, When sulfur is heated,

the packing of the Sthe packing of the S88

molecules changes molecules changes around 96 around 96 ooC.C.

Another form of sulfur is Another form of sulfur is monoclinic sulfur. It is monoclinic sulfur. It is stable between 96-119 stable between 96-119 ooC.C.

When liquid sulfur is When liquid sulfur is heated (160-195 heated (160-195 ooC), it C), it polymerizes into chains polymerizes into chains up to 200 000 S long.up to 200 000 S long.

SS S

S

SSS

S

S S S S S S S S

S S S

S S S S S S

SSSS

S S

S

S S S

S S S S S S

SSSS

S S

S

160-195 oC

160-195 oC

SulfurSulfur

When liquid sulfur polymerizes, its viscosity increases by When liquid sulfur polymerizes, its viscosity increases by a factor of at least 10 000.a factor of at least 10 000.

This is because the long chains tend to get tangled This is because the long chains tend to get tangled up in each other.up in each other.

Sulfur reactivitySulfur reactivity Sulfur is quite a reactive element.Sulfur is quite a reactive element.

It will react will all elements except nitrogen, tellurium, It will react will all elements except nitrogen, tellurium, iodine, iridium, platinum, gold and the noble gases.iodine, iridium, platinum, gold and the noble gases.

Heating may be necessary to bring about a reaction.Heating may be necessary to bring about a reaction.

Compounds of all elements except the noble gases Compounds of all elements except the noble gases with sulfur are known.with sulfur are known.

Although it is reactive, sulfur can be found in nature in Although it is reactive, sulfur can be found in nature in free as well as combined form.free as well as combined form.

Sulfur productionSulfur production Free sulfur Free sulfur

occurs in rock occurs in rock over salt domes over salt domes near the coast near the coast of East Texas of East Texas and Louisiana and Louisiana and under the and under the Gulf of Mexico. Gulf of Mexico. It is mined by It is mined by the Frasch the Frasch process.process.

Superheatedwater

Compressedhot air

Sulfur

MoltenSulfur

Sulfuric acid and sulfatesSulfuric acid and sulfatesSulfuric acidSulfuric acid

It is the cheapest strong acid.It is the cheapest strong acid.

Concentrated sulfuric acid is an oxidizing agent -- but Concentrated sulfuric acid is an oxidizing agent -- but only when hot.only when hot.

CuCu (s) (s) + 2H + 2H22SOSO44 (conc) CuSO (conc) CuSO44 (aq) + 2H (aq) + 2H22O (l) + SOO (l) + SO22 (g) (g)

When cold, it will not oxidize copper.When cold, it will not oxidize copper.

It is such a powerful dehydrating agent, it can char many It is such a powerful dehydrating agent, it can char many organic substances (sugar dehydration-products are C organic substances (sugar dehydration-products are C and waterand water

heat

Produced by the contact process-Sulfur Produced by the contact process-Sulfur is burned in air to form sulfur dioxide, is burned in air to form sulfur dioxide, then sulfur dioxide combines w/more then sulfur dioxide combines w/more oxygen in presence of vanadium(V)oxide oxygen in presence of vanadium(V)oxide to form sulfur trioxide; sulfur trioxide to form sulfur trioxide; sulfur trioxide combines w/water to form sulfuric acidcombines w/water to form sulfuric acid

Dilute sulfuric acid combines w/ metals, Dilute sulfuric acid combines w/ metals, oxides, hydroxides or carbonates to form oxides, hydroxides or carbonates to form sulfate saltssulfate salts

Sulfuric acid and sulfatesSulfuric acid and sulfates

Sulfuric acid and sulfatesSulfuric acid and sulfates Some important sulfatesSome important sulfates Aluminum sulfateAluminum sulfate

• AlAl22(SO(SO44))33

• Produced from AlProduced from Al22OO33..22HH22O (bauxite)O (bauxite)

• Used to treat waterUsed to treat water

• Used to size paper - fill pores.Used to size paper - fill pores.

Ammonium sulfateAmmonium sulfate• (NH(NH44))22SOSO44

• Produced by reaction of HProduced by reaction of H22SOSO44 and NH and NH33

• Used in fertilizers.Used in fertilizers.

Oxides of sulfurOxides of sulfurA number of oxides are known to exist but SOA number of oxides are known to exist but SO22

and SOand SO33 are the most stable and important. are the most stable and important.

Sulfur dioxide - SOSulfur dioxide - SO22

Colorless gas with a sharp odor; harmful to Colorless gas with a sharp odor; harmful to animal and plant life; produced by combustion animal and plant life; produced by combustion of sulfur-containing fuels, volcanoes and air of sulfur-containing fuels, volcanoes and air oxidation of marsh gases.oxidation of marsh gases.

Is oxidized to SOIs oxidized to SO33 by air oxidation. by air oxidation.

Oxides of sulfurOxides of sulfur Sulfur trioxide - SOSulfur trioxide - SO33

It is a liquid under ordinary conditions. Difficult to It is a liquid under ordinary conditions. Difficult to handle because it reacts vigorously with many handle because it reacts vigorously with many materials. It is an anhydride of sulfuric acid.materials. It is an anhydride of sulfuric acid.

SOSO33 (g) (g) + H + H22OO (l) (l) H H22SOSO44 (l) (l)

It, along with NOIt, along with NO22, HCl, SO, HCl, SO22, accounts for the , accounts for the

acidity of acid rain.acidity of acid rain.

Other Group 6A elementsOther Group 6A elements

Selenium is a semi-conductor; poor Selenium is a semi-conductor; poor conductor of electricity in dark, good in conductor of electricity in dark, good in light; this makes it useful in photovoltaic light; this makes it useful in photovoltaic cells, also used in photocopying cells, also used in photocopying machinesmachines

Te is rare, and its compounds are toxicTe is rare, and its compounds are toxic

Halogens, Group 7AHalogens, Group 7A

Do not exist in nature uncombined, but their Do not exist in nature uncombined, but their compounds are abundant; many of their compounds are abundant; many of their sodium salts (NaF, NaI,NaCl,NaBr) are found sodium salts (NaF, NaI,NaCl,NaBr) are found in seawater; CaFin seawater; CaF22 is fluorspar- a mineral is fluorspar- a mineral

All are nonmetalsAll are nonmetals Fluorine and chlorine are gases and yellowish Fluorine and chlorine are gases and yellowish

to green; bromine is dark red liquid, iodine is a to green; bromine is dark red liquid, iodine is a black solid ( vapors are purple)black solid ( vapors are purple)

All are very reactive ( they only need 1eAll are very reactive ( they only need 1e --))

Most are water solubleMost are water soluble All hydrogen halides, except HF, form All hydrogen halides, except HF, form

strong acids ( hi ionization)strong acids ( hi ionization)

Halogens, Group 7AHalogens, Group 7A

ChlorineChlorine Chlorine is 10th in the Top 50 list of chemicals Chlorine is 10th in the Top 50 list of chemicals

produced.produced.

It is a yellow, pungent and highly corrosive gas.It is a yellow, pungent and highly corrosive gas.

ClCl22 is too reactive to occur free in nature. is too reactive to occur free in nature.

Chlorine occurs mostly as sodium chloride in salt Chlorine occurs mostly as sodium chloride in salt waters and mineral deposits.waters and mineral deposits.

Industrial preparation - electrolysis of NaCl.Industrial preparation - electrolysis of NaCl.

2NaCl2NaCl (aq) (aq) + 2H+ 2H22OO (l) (l) 2NaOH 2NaOH (aq) (aq) + Cl+ Cl22 (g) (g) + H+ H22 (g) (g)

ChlorineChlorineUsesUses

About 70% of all chlorine is used in the chemical industry. In many About 70% of all chlorine is used in the chemical industry. In many cases, the final compound does not even contain chlorine.cases, the final compound does not even contain chlorine.

About 20% is used to bleach wood pulp and paper to make it About 20% is used to bleach wood pulp and paper to make it white.white.

Another 5% is used for water treatment.Another 5% is used for water treatment.

Household bleach is made by allowing chlorine to react with Household bleach is made by allowing chlorine to react with NaOH.NaOH.

ClCl22 (aq) + 2NaOH (aq) NaOCl (aq) + NaCl (aq) + H (aq) + 2NaOH (aq) NaOCl (aq) + NaCl (aq) + H22O (l)O (l)

Also used to make vinyl chloride and polyvinyl chloride (PVC)Also used to make vinyl chloride and polyvinyl chloride (PVC)

Hydrochloric acidHydrochloric acid HCl is 27th on the Top 50 list of chemicals.HCl is 27th on the Top 50 list of chemicals.

Most is produced as a by-product of the chlorination Most is produced as a by-product of the chlorination of organic compounds.of organic compounds.

CHCH44 (g) (g) + 2Cl + 2Cl22 (g) (g) CH CH22ClCl22 (l) (l) + 2HCl + 2HCl (g) (g)

Hydrochloric acid is a strong acid.Hydrochloric acid is a strong acid.

Concentrated HCl is produced by saturation of water Concentrated HCl is produced by saturation of water - approximately 12M.- approximately 12M.

In the hardware store, you would find it under the In the hardware store, you would find it under the name muriatic acid.name muriatic acid.

Chlorine oxidesChlorine oxides

Two oxides are made industrially, dichlorine Two oxides are made industrially, dichlorine monoxide and chlorine dioxide.monoxide and chlorine dioxide.

Both are used for bleaching paper and flour.Both are used for bleaching paper and flour.

A radical, ClO, has been studied as a result of A radical, ClO, has been studied as a result of the role it plays in destruction of the ozone the role it plays in destruction of the ozone layer. Using Freon-12 as an example, CCllayer. Using Freon-12 as an example, CCl22FF22::

FluorineFluorine

Made by electrolyzing an ice-cold solution of Made by electrolyzing an ice-cold solution of KF in HF (1886- Henri Moissan)KF in HF (1886- Henri Moissan)

Most chemically reactive of all nonmetalsMost chemically reactive of all nonmetals Strong oxidizing agentStrong oxidizing agent Forms compounds w/ elements except He, Ne, Forms compounds w/ elements except He, Ne,

ArAr HF acid is used to etch glassHF acid is used to etch glass Used to separate the isotopes of UraniumUsed to separate the isotopes of Uranium

Iodine and BromineIodine and Bromine

Br is obtained from sea water and salt-well Br is obtained from sea water and salt-well brinesbrines

2NaBr2NaBr(aq) (aq) + Cl+ Cl2(g)2(g)------2NaCl------2NaCl(aq)(aq) + Br + Br2(l)2(l)

Iodine used to be extracted from ashes of Iodine used to be extracted from ashes of seaweeds; now it is produced from sodium seaweeds; now it is produced from sodium iodate ( NaIOiodate ( NaIO33))

Iodine is necessary for the thyroid gland to work Iodine is necessary for the thyroid gland to work properlyproperly