Chapter 7: Ionic and Metallic Bonding

Chapter 7: Ionic and Chapter 7: Ionic and Metallic BondingMetallic Bonding

7.1 Ions7.1 Ions

Valence ElectronsValence Electrons

Valence electronsValence electrons are the are the electrons in the highest electrons in the highest occupied energy level of an occupied energy level of an element’s atoms.element’s atoms.

The number of valence electrons The number of valence electrons largely determines the chemical largely determines the chemical properties of an element.properties of an element.

7.1

Valence ElectronsValence Electrons

To find the number of valence To find the number of valence electrons in an atom of a electrons in an atom of a representative element, representative element, simply look at its group simply look at its group number.number.

7.1

Valence ElectronsValence Electrons Electron dot structuresElectron dot structures are are

diagrams that show valence diagrams that show valence electrons as dots.electrons as dots.

7.1

The Octet RuleThe Octet Rule Noble gases, such as neon and argon, are Noble gases, such as neon and argon, are

unreactive in chemical reactions. In 1916, chemist unreactive in chemical reactions. In 1916, chemist Gilbert Lewis used this fact to explain why atoms Gilbert Lewis used this fact to explain why atoms form certain kinds of ions and molecules.form certain kinds of ions and molecules.

He called his explanation the He called his explanation the octet octet rule:rule: In forming compounds, In forming compounds, atoms tend to achieve the electron atoms tend to achieve the electron configuration of a noble gas.configuration of a noble gas.

7.1

The Octet RuleThe Octet Rule Atoms of metals tend to lose their Atoms of metals tend to lose their

valence electrons, leaving a valence electrons, leaving a complete octet in the next-lowest complete octet in the next-lowest energy level. Atoms of some non-energy level. Atoms of some non-metals tend to gain electrons or to metals tend to gain electrons or to share electrons with another share electrons with another nonmetal to achieve a complete nonmetal to achieve a complete octet.octet.

7.1

Formation of CationsFormation of Cations

An atom’s loss of valence An atom’s loss of valence electrons produces a cation, electrons produces a cation, or a positively charged ion.or a positively charged ion.

7.1

Formation of Formation of CationsCations

Cations of Group Cations of Group 1A elements 1A elements always have a always have a charge of 1+. charge of 1+. Cations of group Cations of group 2A elements 2A elements always have a always have a charge of 2+.charge of 2+.

7.1

Formation of AnionsFormation of Anions The gain of negatively The gain of negatively

charged electrons by a neutral charged electrons by a neutral atom produces an anion.atom produces an anion.An anion is an atom or a group An anion is an atom or a group of atoms with a negative charge.of atoms with a negative charge.

The name of an anion typically The name of an anion typically ends in -ends in -ideide..

7.1

Formation Formation of Anionsof Anions

The figure The figure shows the shows the symbols of symbols of anions formed anions formed by some by some elements in elements in Groups 5A, Groups 5A, 6A, and 7A.6A, and 7A.

7.1

Formation of AnionsFormation of Anions The ions that are produced when atoms of The ions that are produced when atoms of

chlorine and other halogens gain electrons chlorine and other halogens gain electrons are called are called halide ionshalide ions..All halogen atoms have seven valence All halogen atoms have seven valence electrons.electrons.

All halogen atoms need to gain only one All halogen atoms need to gain only one electron to achieve the electron electron to achieve the electron configuration of a noble gas.configuration of a noble gas.

7.1

Conceptual Problem 7.1Conceptual Problem 7.1

7.1

Practice Problems For Practice Problems For Conceptual Problem 7.1Conceptual Problem 7.1

7.1 Section Quiz.7.1 Section Quiz. 1. How many valence 1. How many valence

electrons are there in an atom electrons are there in an atom of oxygen?of oxygen?

a) 2a) 2

b) 4b) 4

c) 6c) 6

d) 8d) 8

7.1 Section Quiz.7.1 Section Quiz. 2. Atoms that tend to gain a 2. Atoms that tend to gain a

noble gas configuration by losing noble gas configuration by losing valence electrons arevalence electrons are

a) metals.a) metals.

b) nonmetals.b) nonmetals.

c) noble gases.c) noble gases.

d) representative elements.d) representative elements.

3. When a magnesium atom 3. When a magnesium atom forms a cation, it does so byforms a cation, it does so by

a) losing two electrons.a) losing two electrons.

b) gaining two electrons.b) gaining two electrons.

c) losing one electron.c) losing one electron.

d) gaining one electron.d) gaining one electron.

7.1 Section Quiz.7.1 Section Quiz.

4. When a bromine atom forms 4. When a bromine atom forms an anion, it does so byan anion, it does so by

a) losing two electrons.a) losing two electrons.

b) gaining two electrons.b) gaining two electrons.

c) losing one electron.c) losing one electron.

d) gaining one electrond) gaining one electron


7.2 Ionic Bonds and Ionic 7.2 Ionic Bonds and Ionic CompoundsCompounds

Formation of Ionic Formation of Ionic CompoundsCompounds

Compounds composed of Compounds composed of cations and anions are called cations and anions are called ionic compounds.ionic compounds.Although they are composed Although they are composed of ions, ionic compounds are of ions, ionic compounds are electrically neutral.electrically neutral.

7.2

Ionic BondsIonic BondsThe electrostatic forces that The electrostatic forces that hold ions together in ionic hold ions together in ionic compounds are called compounds are called ionic ionic bonds.bonds.

7.2

Formation of Ionic Formation of Ionic CompoundsCompounds

Formula UnitsFormula UnitsA A chemical formulachemical formula shows the kinds shows the kinds and numbers of atoms in the smallest and numbers of atoms in the smallest representative unit of a substance.representative unit of a substance.

A A formula unitformula unit is the lowest whole- is the lowest whole-number ratio of ions in an ionic number ratio of ions in an ionic compound.compound.

7.2

Conceptual Problem Conceptual Problem 7.27.2

for Conceptual Problem 7.2for Conceptual Problem 7.2

Properties of Ionic Properties of Ionic CompoundsCompounds

Most ionic compounds are Most ionic compounds are crystalline solids at room crystalline solids at room temperature. temperature.

Ionic compounds generally Ionic compounds generally have high melting points.have high melting points.

7.2

Properties of Ionic Properties of Ionic CompoundsCompounds

The The coordination numbercoordination number of an ion is of an ion is the number of ions of opposite charge the number of ions of opposite charge that surround the ion in a crystal.that surround the ion in a crystal.

In NaCl, each ion has a coordination In NaCl, each ion has a coordination number of 6.number of 6.

7.2

Ionic compounds can conduct an electric Ionic compounds can conduct an electric current when melted or dissolved in water.current when melted or dissolved in water.

7.2

1. Which chemical formula is 1. Which chemical formula is incorrect?incorrect?

a)a) KFKF22

b)b) CaSCaS

c)c) MgOMgO

d)d) NaBrNaBr


2. Ionic compounds can conduct an 2. Ionic compounds can conduct an electric currentelectric current

a)a) only when melted.only when melted.

b)b) when melted or dissolved in when melted or dissolved in water.water.

c)c) only when dissolved in water.only when dissolved in water.

d)d) when solid or melted.when solid or melted.


3. At room temperature, most 3. At room temperature, most ionic compounds areionic compounds are

a)a) crystalline solids.crystalline solids.

b)b) liquids.liquids.

c)c) gases.gases.

d)d) soft, low melting-point soft, low melting-point solids.solids.


7.3 Bonding in Metals7.3 Bonding in Metals

Metallic Bonds and Metallic Metallic Bonds and Metallic PropertiesProperties

The valence electrons of metal atoms The valence electrons of metal atoms can be modeled as a sea of electrons.can be modeled as a sea of electrons.The valence electrons are mobile and The valence electrons are mobile and can drift freely from one part of the can drift freely from one part of the metal to another.metal to another.Metallic bonds consist of the attraction of Metallic bonds consist of the attraction of the free-floating valence electrons for the the free-floating valence electrons for the positively charged metal ions.positively charged metal ions.

7.3

Metallic Bonds and Metallic Metallic Bonds and Metallic PropertiesProperties

Metals are Metals are ductile—that is, ductile—that is, they can be they can be drawn into drawn into wires.wires.

7.3

A force can change the shape of A force can change the shape of a metal. A force can shatter an a metal. A force can shatter an ionic crystal.ionic crystal.

7.3

Metal atoms are arranged in Metal atoms are arranged in very compact and orderly very compact and orderly patterns.patterns.

7.3

AlloysAlloysAlloysAlloys are mixtures composed are mixtures composed of two or more elements, at of two or more elements, at least one of which is a metal.least one of which is a metal.Alloys are important because Alloys are important because their properties are often their properties are often superior to those of their superior to those of their component elements.component elements.

7.3

AlloysAlloys The most important The most important

alloys today are alloys today are steels. Steels have a steels. Steels have a wide range of useful wide range of useful properties, such as properties, such as corrosion resistance, corrosion resistance, ductility, hardness, ductility, hardness, and toughness.and toughness.

7.3

1.1. The valence electrons of The valence electrons of metals can be modeled asmetals can be modeled as

a)a) a body-centered cube.a body-centered cube.

b)b) octets of electrons.octets of electrons.

c)c) a rigid array of a rigid array of electrons.electrons.

d)d) a sea of electrons.a sea of electrons.


2. 2. In most metals, the atoms areIn most metals, the atoms are

a) free to move from one part of a) free to move from one part of the metal to another.the metal to another.

b) arranged in a compact and b) arranged in a compact and orderly pattern.orderly pattern.

c) placed at irregular locations.c) placed at irregular locations.

d) randomly distributed.d) randomly distributed.


3. 3. Alloys are important because theyAlloys are important because they

a) are pure substances.a) are pure substances.

b) are the ores from which metals can b) are the ores from which metals can be be refined.refined.

c) can have properties superior to c) can have properties superior to those those of their components.of their components.

d) are produced by the combustion of d) are produced by the combustion of metals.metals.


9.1 Naming Ions9.1 Naming Ions

Monatomic IonsMonatomic Ions

Monatomic ionsMonatomic ions consist of a consist of a single atom with a positive or single atom with a positive or negative charge resulting negative charge resulting from the loss or gain of one or from the loss or gain of one or more valence electrons, more valence electrons, respectively.respectively.

9.1


CationsCationsWhen the metals in Groups When the metals in Groups 1A, 2A, and 3A lose 1A, 2A, and 3A lose electrons, they form cations electrons, they form cations with positive charges equal with positive charges equal to their group number.to their group number.

9.1


The names of the cations of The names of the cations of the Group 1A, Group 2A, and the Group 1A, Group 2A, and Group 3A metals are the Group 3A metals are the same as the name of the same as the name of the metal, followed by the word metal, followed by the word ionion or or cationcation..

9.1

Monatomic IonsMonatomic Ions AnionsAnions

The charge of any ion of a The charge of any ion of a Group A nonmetal is Group A nonmetal is determined by subtracting determined by subtracting 8 from the group number.8 from the group number.

Anion names start with Anion names start with the stem of the the stem of the element name and end element name and end in in -ide-ide..

9.1


The charges of the cations of The charges of the cations of many transition metal ions many transition metal ions must be determined from the must be determined from the number of electrons lost.number of electrons lost.

9.1


In the Stock system, a Roman In the Stock system, a Roman numeral in parentheses is numeral in parentheses is placed after the name of the placed after the name of the element to indicate the element to indicate the numerical value of the numerical value of the charge.charge.

9.1

Conceptual Problem 9.1Conceptual Problem 9.11.1


Polyatomic IonsPolyatomic Ions

Some ions, called Some ions, called polyatomic polyatomic ionsions, are composed of more , are composed of more than one atom. than one atom. The names of most The names of most polyatomic anions end in -polyatomic anions end in -iteite or -or -ateate..

9.1

Polyatomic IonsPolyatomic Ions

Names and Names and Formulas of Some Formulas of Some Common Common Polyatomic IonsPolyatomic Ions

9.1

9.1 Section Quiz.9.1 Section Quiz. 1.1. When metals from groups 1A, When metals from groups 1A,

2A, and 3A form cations, the charge 2A, and 3A form cations, the charge on the ion is equal toon the ion is equal to

a)a) 8 minus the group number.8 minus the group number.

b)b) the group number minus 8.the group number minus 8.

c)c) the period number.the period number.

d)d) the group number.the group number.

2.2. Which of the following are positively Which of the following are positively charged polyatomic ions?charged polyatomic ions?

(I) ammonium ion(I) ammonium ion (II) perchlorate ion(II) perchlorate ion (III) ferric ion(III) ferric ion

a)a) I onlyI only

b)b) II onlyII only

c)c) III onlyIII only

d)d) I and III I and III

3.3. If the name of an ion ends in If the name of an ion ends in -ite-ite or or -ate-ate, the ion is a , the ion is a

a)a) polyatomic cation.polyatomic cation.

b)b) polyatomic anion.polyatomic anion.

c)c) transition metal cation.transition metal cation.

d)d) monatomic anion.monatomic anion.

9.1 Section Quiz9.1 Section Quiz

9.2 Naming and 9.2 Naming and Writing Formulas for Writing Formulas for

Ionic CompoundsIonic Compounds

Binary Ionic CompoundsBinary Ionic CompoundsNaming Binary Ionic CompoundsNaming Binary Ionic Compounds

A A binary compoundbinary compound is composed is composed of two elements and can be either of two elements and can be either ionic or molecular. ionic or molecular. To name any binary ionic To name any binary ionic compound, place the cation name compound, place the cation name first, followed by the anion name.first, followed by the anion name.

9.2

Naming Binary IonicNaming Binary Ionic

1)1) CsFCsF

2)2) AlClAlCl333)3) MgIMgI22

4)4) RbRb22OO

5)5) SrISrI22

6) K6) K22SS 7) KCl7) KCl 8) ZnS8) ZnS 9) CaBr9) CaBr22

10) Al10) Al22SS33

Naming Binary Ionic with Naming Binary Ionic with Transition MetalsTransition Metals

1)1) CuClCuCl

2)2) HgOHgO

3)3) FeFe22OO33

4)4) MnOMnO22

5)5) PbClPbCl44

6) CoCl6) CoCl33

7) CuI7) CuI 8) SnBr8) SnBr44

9) HgCl9) HgCl22 10) PbS10) PbS

Mixed Naming Binary IonicMixed Naming Binary Ionic

1)1) CoBrCoBr22

2)2) CaClCaCl223)3) AlAl22OO33

4)4) CrClCrCl335)5) SnISnI44

6) K6) K33NN 7) RbF7) RbF 8) NaH8) NaH 9) CrF9) CrF22

10) MgBr10) MgBr22

Binary Ionic CompoundsBinary Ionic Compounds

Writing Formulas for Binary Writing Formulas for Binary Ionic CompoundsIonic Compounds

Write the symbol of the Write the symbol of the cation and then the anion. cation and then the anion. Add whatever subscripts Add whatever subscripts are needed to balance the are needed to balance the charges.charges.

9.2

Conceptual Problem 9.2Conceptual Problem 9.2

9.2

Sample Problems For Sample Problems For Conceptual Problem 9.2Conceptual Problem 9.2

Write Formulas for:Write Formulas for:

1) calcium chloride1) calcium chloride 2) lead (IV) oxide2) lead (IV) oxide 3) aluminum oxide3) aluminum oxide 4) magnesium bromide4) magnesium bromide 5) cesium fluoride5) cesium fluoride

Write formulas forWrite formulas for

Iron (II) oxideIron (II) oxide Iron (III) oxideIron (III) oxide Potassium bromidePotassium bromide Aluminum sulfideAluminum sulfide Lithium oxideLithium oxide

Compounds With Polyatomic Compounds With Polyatomic IonsIons

Write the symbol for the Write the symbol for the cation followed by the cation followed by the formula for the polyatomic formula for the polyatomic ion and balance the ion and balance the charges.charges.

9.2

Conceptual Problem 9.3Conceptual Problem 9.39.3


Write formulas for:Write formulas for:

1) lithium perchlorate1) lithium perchlorate 2) potassium acetate2) potassium acetate 3) cesium sulfite3) cesium sulfite 4) cobalt (III) hydroxide4) cobalt (III) hydroxide 5) sodium hypochlorite5) sodium hypochlorite

Write formulas for:Write formulas for:

1) ammonium nitrite1) ammonium nitrite 2) sodium perchlorate2) sodium perchlorate 3) barium acetate3) barium acetate 4) aluminum hydroxide4) aluminum hydroxide 5) calcium nitrate5) calcium nitrate

Compounds With Polyatomic Compounds With Polyatomic IonsIons

Naming Compounds with Naming Compounds with Polyatomic IonsPolyatomic Ions

To name a compound containing To name a compound containing a polyatomic ion, state the a polyatomic ion, state the cation first and then the anion, cation first and then the anion, just as you did in naming binary just as you did in naming binary ionic compounds.ionic compounds.

9.2

Naming PolyatomicsNaming Polyatomics

1) Na1) Na22SOSO44

2) KH2) KH22POPO44

3) Fe(NO3) Fe(NO33))33

4) Mn(OH)4) Mn(OH)22

5) Na5) Na22SOSO33

6) Ca(OH)6) Ca(OH)22

7) Na7) Na33POPO44

8) KMnO8) KMnO44

9) (NH9) (NH44))22CrCr22OO77

10) Co(ClO10) Co(ClO44))22

Naming PolyatomicsNaming Polyatomics

1) KClO1) KClO33

2) Cu(NO2) Cu(NO22))22

3) Cu(NO3) Cu(NO33))22

4) PbCO4) PbCO33

5) KHSO5) KHSO44

6) NH6) NH44II 7) NaCN7) NaCN 8) Na8) Na22COCO33

9) CuSO9) CuSO44

10) CsClO10) CsClO44

9.2 Section Quiz9.2 Section Quiz1.1. The correct name for CrClThe correct name for CrCl33 isis

a) chromium chlorine.a) chromium chlorine.

b) chromium(III) chloride.b) chromium(III) chloride.

c) monochromium trichloride.c) monochromium trichloride.

d) chromium(III) trichloride.d) chromium(III) trichloride.

2.2. What is the correct formula What is the correct formula for strontium nitride?for strontium nitride?

a) Sra) Sr33NN22

b) SrNb) SrN22

c) Src) Sr22NN33

d) Srd) Sr33NN


3.3. Which one of the following Which one of the following compounds is named correctly?compounds is named correctly?

a) sodium chlorite, NaClOa) sodium chlorite, NaClO

b) potassium nitrate, KNOb) potassium nitrate, KNO22

c) sodium acetate, NaCc) sodium acetate, NaC22HH33OO22

d) lithium sulfate, Lid) lithium sulfate, Li22SOSO33


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Chapter 7: Ionic and Metallic Bonding

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