Chapter 8

Chapter 8Chapter 8

Ionic BondingIonic Bonding

Question of the DayQuestion of the Day

Question: Write the electron level configurations Question: Write the electron level configurations for the Noble gases.for the Noble gases.

He He ArAr

Kr Kr XeXe

I. Chemical BondsI. Chemical Bonds

A. The force that holds two atoms together.A. The force that holds two atoms together. 1. Why do atoms form bonds?1. Why do atoms form bonds? a. to acquire 8 electrons in thea. to acquire 8 electrons in the valence shell (like noble gases valence shell (like noble gases

2. How do atoms form bonds? 2. How do atoms form bonds? a. atoms may lose, gain or sharea. atoms may lose, gain or share electrons to get 8 in the valenceelectrons to get 8 in the valence shellshell

A. Chemical Bond and A. Chemical Bond and valence electron valence electron

1.The electrons responsible for the chemical 1.The electrons responsible for the chemical properties of atoms are those in the outer properties of atoms are those in the outer energy level: energy level: VALENCE ELECTRONS.VALENCE ELECTRONS.

a.Valence electrons - The electrons in a.Valence electrons - The electrons in the outer energy level.the outer energy level.

b.Inner electrons -those in the energy b.Inner electrons -those in the energy levels below. levels below.

Keeping Track of ElectronsKeeping Track of Electrons

2. Atoms in the same column2. Atoms in the same columna. Have the same outer electron configuration.a. Have the same outer electron configuration.

b. Have the same valence electrons.b. Have the same valence electrons.

c. Easily found by looking up the group number c. Easily found by looking up the group number on the periodic table.on the periodic table.

d. Group 2A - Be, Mg, Ca, etc.-d. Group 2A - Be, Mg, Ca, etc.-

2 valence electrons2 valence electrons

B. Electron Dot Diagrams: Lewis B. Electron Dot Diagrams: Lewis StructuresStructures

1. A way of keeping track of 1. A way of keeping track of valence electrons.valence electrons.

2. How to write them2. How to write them3. Write the symbol.3. Write the symbol.4. Put one dot for each valence 4. Put one dot for each valence

electronelectron5. Don’t pair up until they have to5. Don’t pair up until they have to

X

The Electron Dot diagram for Nitrogen

Nitrogen has 5 valence electrons.

First we write the symbol.

NThen add 1 electron at a time to each side.Until they are forced to pair up.

Write the electron dot diagram Write the electron dot diagram forfor

NaNa MgMg CC OO FF NeNe HeHe

C. Ion Formation in Representative C. Ion Formation in Representative ElementsElements

GroupGroup Gain or Lose Gain or Lose Charge of Ion Charge of Ion1 (1A) lose 1 +11 (1A) lose 1 +12 (2A) lose 2 +2 2 (2A) lose 2 +2 13 (3A) lose 3 +313 (3A) lose 3 +314 (4A) lose or gain 4* +4,-4*14 (4A) lose or gain 4* +4,-4*15 (5A) gain 3 -315 (5A) gain 3 -316 (6A) gain 2 -216 (6A) gain 2 -217 (7A) gain 1 -117 (7A) gain 1 -1

C. Electron Configurations for C. Electron Configurations for CationsCations

1. Metals lose electrons to attain noble gas 1. Metals lose electrons to attain noble gas configuration.configuration.

2. They make positive ions.2. They make positive ions.

3. If we look at electron configuration it makes 3. If we look at electron configuration it makes sense.sense.

Na 1sNa 1s222s2s222p2p663s3s11:: 1 valence electron 1 valence electron

NaNa++ 1s 1s222s2s222p2p6 6 :: noble gas configurationnoble gas configuration

Electron Dots For CationsElectron Dots For Cations

Metals will have few valence electronsMetals will have few valence electrons

Ca


Metals will have few valence electronsMetals will have few valence electrons These will come offThese will come off

Ca


Metals will have few valence electronsMetals will have few valence electrons These will come offThese will come off Forming positive ionsForming positive ions

Ca+2

Write the electron Write the electron configuration diagram label as configuration diagram label as

anion or cation anion or cation NaNa MgMg PP OO FF ClCl KK

D. Electron Configurations for D. Electron Configurations for AnionsAnions

1. Nonmetals gain electrons to attain noble 1. Nonmetals gain electrons to attain noble gas configuration.gas configuration.

2. They make negative ions.2. They make negative ions.3. If we look at electron configuration it 3. If we look at electron configuration it

makes sense.makes sense. S 1sS 1s222s2s222p2p663s3s223p3p44: 6 valence electrons: 6 valence electrons SS-2-2 1s 1s222s2s222p2p663s3s223p3p66:: noble gas noble gas

configuration.configuration.

Electron Dots For AnionsElectron Dots For Anions

Nonmetals will have many Nonmetals will have many valence .electrons.valence .electrons.

They will gain electrons to fill outer shell.They will gain electrons to fill outer shell.

P P-3

E. Stable Electron ConfigurationE. Stable Electron Configuration

1.All atoms react to achieve noble gas configuration.1.All atoms react to achieve noble gas configuration.

2.Noble gases have 2 s and 6 p electrons.2.Noble gases have 2 s and 6 p electrons.

3. 8 valence electrons .3. 8 valence electrons .

4. Also called the octet rule.4. Also called the octet rule.

Ar

I. Properties of Ionic CompoundsI. Properties of Ionic Compounds

View Ionic videoView Ionic video

a. Crystalline structure.a. Crystalline structure.

b. A regular repeating arrangement of ions in b. A regular repeating arrangement of ions in the solid.the solid.

c. Structure is rigid.c. Structure is rigid.

Ionic_Bonds.asf

II. Ionic BondingII. Ionic Bonding

A. Anions and cations are held together by A. Anions and cations are held together by opposite charges.opposite charges.

B. Ionic compounds are called salts.B. Ionic compounds are called salts.

C. Simplest ratio is called the formula unit.C. Simplest ratio is called the formula unit.

D.The bond is formed through the transfer of D.The bond is formed through the transfer of electrons.electrons.

E. Electrons are transferred to achieve noble E. Electrons are transferred to achieve noble gas configuration.gas configuration.

II.II. Formation and Nature of Ionic BondsFormation and Nature of Ionic Bonds

FF. 1. atom “M” loses electron(s) . 1. atom “M” loses electron(s) cationcation

2. atom “N” gains electron(s) 2. atom “N” gains electron(s) anionanion

3. cation and anion attract each other3. cation and anion attract each other

a. electrostatic attractiona. electrostatic attraction

4. the 4. the electrostatic forceelectrostatic force that holds the that holds the

oppositely charged ions together isoppositely charged ions together is

the ionic bondthe ionic bond

Sodium loses an electron forming a (+) ion. Sodium loses an electron forming a (+) ion. Chlorine gains an electron forming a ( - ) ion.Chlorine gains an electron forming a ( - ) ion.

Electrostatic attraction between the (-) and (+) ion forms Electrostatic attraction between the (-) and (+) ion forms the ionic bond between sodium and chlorinethe ionic bond between sodium and chlorine

B. Ionic CompoundsB. Ionic Compounds 1. compounds containing ionic bonds1. compounds containing ionic bonds 2. types of ionic compounds2. types of ionic compounds a. a. oxidesoxides – metal + oxygen– metal + oxygen

NaNa22O, CaO, AlO, CaO, Al22OO33, Fe, Fe22OO33

b. b. salt salt – metal + nonmetal– metal + nonmetal NaCl CaF AgCl KINaCl CaF AgCl KI c. c. binary compoundsbinary compounds – two elements – two elements 1)all of the compounds in a and b 1)all of the compounds in a and b

are binary compoundsare binary compounds

D. D. monoatomicmonoatomic ionion - one atom - one atom

1) ex. K1) ex. K+ + FeFe3+3+ O O2-2- N N3- 3-

EE. . polyatomic ionpolyatomic ion – ion with more than – ion with more than

one atom that acts as a single ionone atom that acts as a single ion

NONO33-- OH OH-- SO SO44

2-2- NH NH44++

Work on ion formation and the periodic table Work on ion formation and the periodic table worksheet.worksheet.

Complete notes sheetComplete notes sheet

III. Names and FormulasIII. Names and FormulasA.A. Formulas for Ionic CompoundsFormulas for Ionic Compounds 1. vocabulary 1. vocabulary a. a. formula unitformula unit – simplest ratio of – simplest ratio of ions in a compound ions in a compound

1) ex. NaCl MgBr1) ex. NaCl MgBr22 AlCl AlCl33

b.b. monoatomicmonoatomic ion - one atomion - one atom 1) ex. K1) ex. K+ + FeFe3+3+ O O2-2- N N3- 3-

c. c. oxidation numberoxidation number – charge of – charge of the monoatomic ionthe monoatomic ion 1) ex. K is +1 O is -2 N is -31) ex. K is +1 O is -2 N is -3

d. d. polyatomic ionpolyatomic ion – ion with more than – ion with more than one atom that acts as a single ionone atom that acts as a single ion NONO33

-- OH OH-- SO SO442-2- NH NH44

++

2. composition of ionic compounds2. composition of ionic compounds a. metal + nonmetal (NaCl)a. metal + nonmetal (NaCl) b. metal + polyatomic ion(MgSOb. metal + polyatomic ion(MgSO44)) c. polyatomic ion + nonmetal (NHc. polyatomic ion + nonmetal (NH44Cl)Cl) d. polyatomic ion + polyatomic iond. polyatomic ion + polyatomic ion NHNH44NONO3 3

BB. . Formulas For Ionic CompoundsFormulas For Ionic Compounds 1. write formula for the 1. write formula for the cationcation first, then first, then the the anionanion 2. use 2. use subscriptssubscripts to indicate number of to indicate number of ions (criss-cross the charges)ions (criss-cross the charges) a. sum of charges should equal 0a. sum of charges should equal 0 b. never change subscripts inb. never change subscripts in polyatomic ionspolyatomic ions c. put c. put polyatomic ionspolyatomic ions in parentheses in parentheses when there is more than onewhen there is more than one

Sodium Chloride CrystalSodium Chloride Crystal


Na Cl

Ionic Bonding: Lewis StructureIonic Bonding: Lewis Structure

Na+ Cl -


All the electrons must be accounted for!All the electrons must be accounted for!

Ca P


Ca P


Ca+2 P

Ionic Bonding

Ca+2 P

Ca

Ionic Bonding

Ca+2 P-3

Ca

Ionic Bonding

Ca+2 P-3

Ca P

Ionic Bonding

Ca+2 P-3

Ca+2 P

Ionic Bonding

Ca+2 P-3

Ca+2 P

Ca

Ionic Bonding

Ca+2 P-3

Ca+2P

-3

Ca+2

Ionic Bonding

Ca3P2

Formula Unit

Ionic_Bonds.asf

ShortcutShortcut

CaCa+2 +2 PP-3-3

CaCa33PP22

Crisscross the charges to become Crisscross the charges to become the subscript!!!!!!!!!!!!!!!!!!!!!!!!!the subscript!!!!!!!!!!!!!!!!!!!!!!!!!

quizquiz

I. Properties of Ionic CompoundsI. Properties of Ionic Compounds

a. Crystalline structure.a. Crystalline structure.

b. A regular repeating arrangement of b. A regular repeating arrangement of ions in the solid.ions in the solid.

c. Structure is rigid.c. Structure is rigid.

Crystalline structureCrystalline structure

Ionic CompoundsIonic Compounds

Ionic compounds Ionic compounds consist ofconsist of

a a latticelattice

of positiveof positive

and negative ions.and negative ions.

Lattice: three Lattice: three dimensional array of dimensional array of ions ions

NaCl:

Crystalline StructureCrystalline Structure

1. forms a lattice crystal- a 3-d geometric 1. forms a lattice crystal- a 3-d geometric structure.structure.

a. each negative ion is surrounded by a. each negative ion is surrounded by positive ions. b. Lattice energy- the energy positive ions. b. Lattice energy- the energy required to break one mole of ions from the required to break one mole of ions from the ionic bond the more energy – the harder it is to ionic bond the more energy – the harder it is to break-pg 220break-pg 220

Ionic propertiesIonic properties

d. Ions are strongly bonded- because of d. Ions are strongly bonded- because of strong forces between ions they havestrong forces between ions they have

1. High melting points1. High melting points 2. high boiling point2. high boiling point

3. high hardness scale3. high hardness scale4. very rigid4. very rigid5. very brittle5. very brittle

Ionic solids are brittleIonic solids are brittle

+ - + -+- +-

+ - + -+- +-

Ionic solids are brittleIonic solids are brittle

+ - + -

+- +-+ - + -

+- +-

Strong Repulsion breaks crystal apart.Strong Repulsion breaks crystal apart.

ActivityActivity

Demo- Burn to Create Mg+O=MgODemo- Burn to Create Mg+O=MgO Check the conductivity of:Check the conductivity of: 1. NaCl- solid1. NaCl- solid 2. NaCl-aqueous solution2. NaCl-aqueous solution 3. Distilled water3. Distilled water 4. Tap4. Tap 5. MgO-solid5. MgO-solid 6. MgO-aqueous solution6. MgO-aqueous solution 7. use magnifying glass to view NaCl7. use magnifying glass to view NaCl

E. ConductivityE. Conductivity

1.Conducting electricity is allowing charges 1.Conducting electricity is allowing charges to move.to move.

2.In a solid, the ions are locked in place.2.In a solid, the ions are locked in place.3. Ionic solids are insulators.3. Ionic solids are insulators.4. When melted, the ions can move around.4. When melted, the ions can move around.5. Melted ionic compounds conduct.5. Melted ionic compounds conduct.6. First get them to 800ºC.6. First get them to 800ºC.7. ELECTROLYTE-Dissolved in water they 7. ELECTROLYTE-Dissolved in water they

conduct. (aqueous solution)conduct. (aqueous solution)

Building Ionic CompoundsBuilding Ionic Compounds

Binary compound - metallic cation bonded to nonmetallic anion 1. Oxide- When a metal is ionically bonded to

OxygenSalt - Metal + Non-metal

ACTIVITY:

MAKE TAB CUTOUTS OF THE VALENCE SHELL OF AL, O, Na, Cl, Mg, Ca

Bond Al O Mg O Na Cl

Build just one formula unit- remember it doesn’t exist as Build just one formula unit- remember it doesn’t exist as oneone i in nature – it is a crystal of many formula units where each – is surrounded by a +

Polyatomic IonsPolyatomic Ions

An ion made up of two or more atoms bonded An ion made up of two or more atoms bonded together that acts as a single unit with a net together that acts as a single unit with a net charge.charge.

Build with tabs NHBuild with tabs NH4 ,4 ,OH, Write the polyatomic ion OH, Write the polyatomic ion

and the charge it has.and the charge it has.

Na(OH)- a balance compoundNa(OH)- a balance compound

MgMg+2+2(OH(OH) –1) –1

Mg(0H)Mg(0H)2 2 a balanced compounda balanced compound

Naming CompoundsNaming Compounds.A. .A. Formulas For Ionic CompoundsFormulas For Ionic Compounds 1. write formula for the 1. write formula for the cationcation first, then first, then the the anionanion 2. use 2. use subscriptssubscripts to indicate number of to indicate number of ions (criss-cross the charges)ions (criss-cross the charges) a. sum of charges should equal 0a. sum of charges should equal 0 b. never change subscripts inb. never change subscripts in polyatomic ionspolyatomic ions c. put c. put polyatomic ionspolyatomic ions in parentheses in parentheses when there is more than onewhen there is more than one

A.A. Writing Names of Ionic CompoundsWriting Names of Ionic Compounds

1. write name of 1. write name of cationcation first then first then anionanion

a. this is the same order in which a. this is the same order in which

elements appear in the formulaelements appear in the formula

2. use Roman numerals to indicate the2. use Roman numerals to indicate the

valence of the cation if it is valence of the cation if it is multivalentmultivalent

a. examplesa. examples

CuCl - copper I chlorideCuCl - copper I chloride

CuClCuCl22 - copper II chloride - copper II chloride

3. Name a cation with a polyatomic 3. Name a cation with a polyatomic anionanion

A.Name the cation element 1A.Name the cation element 1stst

B. Name the anion polyatomic ion 2ndB. Name the anion polyatomic ion 2nd

ie: NaOH Sodium hydroxideie: NaOH Sodium hydroxide

Naming ionic compoundsNaming ionic compounds

I. Oxyanion- is a polyatomic ( 2 or more ions I. Oxyanion- is a polyatomic ( 2 or more ions bonded) ion where a non-metal bonds with bonded) ion where a non-metal bonds with oxygen.oxygen.

A. use the root of the non-metal with A. use the root of the non-metal with the following suffixthe following suffix

1. MORE OXYGENS - ATE1. MORE OXYGENS - ATE

2. LESS OXYGENS - ITE2. LESS OXYGENS - ITE

IE; NOIE; NO2 2 - Nitrite NO- Nitrite NO33 - Nitrate - Nitrate

Naming the halogen group as an Naming the halogen group as an oxyanionoxyanion

A. use the root of the halogen with the following A. use the root of the halogen with the following suffix and prefixsuffix and prefix

1. Most oxygens ( usually 4 ) 1. Most oxygens ( usually 4 ) a. prefix - per a. prefix - per b. suffix - ateb. suffix - ate

ie: IOie: IO4 4 - periodate- periodate2. one less oxygen2. one less oxygen

a. suffix - ate ioa. suffix - ate ioie: IOie: IO33- iodate- iodate

Halogen as oxyanionsHalogen as oxyanions

3. two less Oxygen- 3. two less Oxygen-

a. suffix - itea. suffix - ite

ie: IO2 - ioditeie: IO2 - iodite

4. 3 less oxygens-4. 3 less oxygens-

a. prefix - hypoa. prefix - hypo

b. suffix- iteb. suffix- ite

ie: IO- hypoioditeie: IO- hypoiodite

I. Metallic BondsI. Metallic Bonds

How atoms are held together in the solid How atoms are held together in the solid form.form.

Metals hold onto their valence electrons Metals hold onto their valence electrons very weakly.very weakly.

Think of them as positive ions floating in a Think of them as positive ions floating in a sea of electrons.sea of electrons.

http://www.youtube.com/watch?v=c4udBSZfLHY



Sea of ElectronsSea of Electrons

+ + + ++ + + +

+ + + +

Electrons are free to move through the solid.Electrons are free to move through the solid. Metals conduct electricity.Metals conduct electricity.

Metals are MalleableMetals are Malleable

Hammered into shape (bend).Hammered into shape (bend). Ductile - drawn into wires.Ductile - drawn into wires.

MalleableMalleable

+ + + ++ + + +

+ + + +

MalleableMalleable

+ + + +

+ + + ++ + + +

Electrons allow atoms to slide by.Electrons allow atoms to slide by.

VideoVideo

http://www.youtube.com/watch?v=Bjf9gMDP47s



ALLOYSALLOYS

Alloys are Alloys are solid solutionssolid solutions made by made by dissolving metals in other metals. They dissolving metals in other metals. They are prepared by melting the metals are prepared by melting the metals together and cooling the mixture.together and cooling the mixture.

The properties of alloys differ from those The properties of alloys differ from those of their component metals. For example of their component metals. For example stainless steelstainless steel, an alloy of iron, carbon, , an alloy of iron, carbon, chromium and nickel is stronger than iron chromium and nickel is stronger than iron and more resistant to corrosion. and more resistant to corrosion.

Name of Alloy CompositionName of Alloy Composition

________________________________________________________________________________

Sterling silver silver, copperSterling silver silver, copper

Brass copper, zinc, tinBrass copper, zinc, tin

Cast iron iron, carbonCast iron iron, carbon

Steel iron, carbonSteel iron, carbon

Stainless steel iron, chromium, carbon, nickleStainless steel iron, chromium, carbon, nickle

18 Carat gold gold, silver, copper18 Carat gold gold, silver, copper

Pewter tin, copper, bismuth, antimonyPewter tin, copper, bismuth, antimony

Plumber’s solder lead, tin Plumber’s solder lead, tin

ALLOYALLOY

A combination of 2 metalsA combination of 2 metals

IV.IV. Metallic Bonds – Properties of MetalsMetallic Bonds – Properties of MetalsA.A. Metallic BondsMetallic Bonds

1. valence electrons are 1. valence electrons are delocalizeddelocalized a. free to move from atom to atoma. free to move from atom to atom 2. bond is formed by the attraction of2. bond is formed by the attraction of metal cations for the moving electronsmetal cations for the moving electrons 3. 3. ““electron sea model”electron sea model” –atoms of –atoms of metals contribute a “sea” of free metals contribute a “sea” of free moving electrons that move from one moving electrons that move from one atom to anotheratom to another

Electron Sea Model for Metallic BondsElectron Sea Model for Metallic Bonds

Positive Ions Surrounded by Delocalized ElectronsPositive Ions Surrounded by Delocalized Electrons

B.B. Properties of MetalsProperties of Metals 1. moderately high melting points1. moderately high melting points 2. high boiling points2. high boiling points 3. 3. malleablemalleable a. can be hammered into sheetsa. can be hammered into sheets 4. 4. ductileductile a. can be drawn into wirea. can be drawn into wire 5. good conductors of heat and electricity5. good conductors of heat and electricity 6. 6. lusterluster (good reflectors of light)(good reflectors of light) 7. hardness and strength varies7. hardness and strength varies a. greater in transition elementsa. greater in transition elements

C. AlloysC. Alloys

1. mixture of two or more elements with1. mixture of two or more elements with

metallic propertiesmetallic properties

2. types2. types

a. a. substitutionalsubstitutional – atoms of similar– atoms of similar

size (sterling silver, brass, pewter)size (sterling silver, brass, pewter)

b. b. interstitialinterstitial – small holes in the – small holes in the

crystal filled with smaller atomscrystal filled with smaller atoms

(carbon steel) (carbon steel)

The red, blue and yellow circles represent threeThe red, blue and yellow circles represent threedifferent metals in an alloy. The blue lines are the different metals in an alloy. The blue lines are the delocalized electrons in the metals.delocalized electrons in the metals.

Substitutional Alloy Interstitial AlloySubstitutional Alloy Interstitial Alloy

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