chem chapt 7

Ionic Ionic Compounds and Compounds and

MetalsMetalsChemistry Chapter 7Chemistry Chapter 7

Main IdeasMain IdeasIons are formed when atoms gain or lose Ions are formed when atoms gain or lose valence electrons to achieve a stable valence electrons to achieve a stable octet electron configuration.octet electron configuration.

Oppositely charged ion attract each other, Oppositely charged ion attract each other, forming electrically neutral ionic forming electrically neutral ionic compounds.compounds.

In written names and formulas for ionic In written names and formulas for ionic compounds, the cation appears first, compounds, the cation appears first, followed by the anion.followed by the anion.

Metals form crystal lattices and can be Metals form crystal lattices and can be modeled as cations surrounded by a modeled as cations surrounded by a “sea’” of freely moving valence electrons.“sea’” of freely moving valence electrons.

Ion FormationIon FormationIons are formed when atoms gain Ions are formed when atoms gain

or lose valence electrons to or lose valence electrons to achieve a stable octet electron achieve a stable octet electron configuration.configuration.

DefineDefine a chemical bond. a chemical bond.

DescribeDescribe the formation of the formation of positive and negative ions.positive and negative ions.

Relate Relate ion formation to electron ion formation to electron configuration.configuration.

Valence Electrons Valence Electrons and Chemical and Chemical

BondsBondsChemical Bond Chemical Bond – is a force that – is a force that holds two atoms together. holds two atoms together.

They can form between the They can form between the positive nucleus of one atom and positive nucleus of one atom and the negative valence electrons of the negative valence electrons of another atom or between two another atom or between two oppositely charged ions. oppositely charged ions.

Valence Electrons Valence Electrons and Chemical and Chemical

BondsBondsAtom’s try to form the octet – the Atom’s try to form the octet – the stable arrangement of eight valence stable arrangement of eight valence electrons in the outer energy level – electrons in the outer energy level – by gaining or losing valence electrons.by gaining or losing valence electrons.

The transfer of valence electrons The transfer of valence electrons between two atoms is based on the between two atoms is based on the ionization energy and electron affinity ionization energy and electron affinity of the two atoms.of the two atoms.

Noble gases- Noble gases- high ionization energy high ionization energy + low electron affinity = little + low electron affinity = little chemical reactivity. chemical reactivity.

Positive Ion Positive Ion FormationFormation

Cation – positively charged ionCation – positively charged ion

Sodium atom:Sodium atom:

1s1s22 2s 2s22pp66 3s 3s11

Sodium ion:Sodium ion:

1s1s22 2s 2s2 2 pp66 = neon = neon


Metal atoms are reactive because Metal atoms are reactive because they lose valence electrons easily.they lose valence electrons easily.

Group 1: commonly form +1 ionsGroup 1: commonly form +1 ions

Group 2: commonly form +2 ionsGroup 2: commonly form +2 ions

Group 13: sometimes +3 ionsGroup 13: sometimes +3 ions


Transition metal ions have an Transition metal ions have an outer shell of souter shell of s22

They will lose their s electrons They will lose their s electrons and occasionally a d electron.and occasionally a d electron.

Typically form +2 or +3 ions but Typically form +2 or +3 ions but can form greater than +3 ionscan form greater than +3 ions


Other relatively stable electron Other relatively stable electron arrangements are referred to as arrangements are referred to as pseudo-noble gas configurations.pseudo-noble gas configurations.

Groups 11-14 will lose electrons to Groups 11-14 will lose electrons to form full outer shells: s, p, and d.form full outer shells: s, p, and d.

Negative Ion Negative Ion FormationFormation

An anion is a negatively charged An anion is a negatively charged ion. (Add “-ide” to the end of the ion. (Add “-ide” to the end of the root atom name.)root atom name.)

Nonmetals easily gain electrons.Nonmetals easily gain electrons.

Chlorine atom:Chlorine atom:

1s1s22 2s 2s22pp66 3s 3s22pp55

Chlorine ion:Chlorine ion:

1s1s22 2s 2s22pp66 3s 3s22pp66 = Argon = Argon

Negative Ion Negative Ion FormationFormation

Nonmetal ions gain the number of Nonmetal ions gain the number of electrons required to fill an octet.electrons required to fill an octet.

Some nonmetals can gain or lose Some nonmetals can gain or lose electrons to complete an octet.electrons to complete an octet.

Phosphorus can gain 3 or lose 5Phosphorus can gain 3 or lose 5

Group 15 usually gains 3 electronsGroup 15 usually gains 3 electrons

Group 16 usually gains 2 electronsGroup 16 usually gains 2 electrons

Group 17 usually gains 1 electronGroup 17 usually gains 1 electron

Practice ProblemsPractice Problems

page 209 #1-6page 209 #1-6

Ionic Bonds and Ionic Bonds and Ionic CompoundsIonic Compounds

Ionic Bonds and Ionic Bonds and Ionic CompoundsIonic CompoundsDescribe the formation of ionic Describe the formation of ionic bonds and the structure of ionic bonds and the structure of ionic compounds.compounds.

Generalize about the strength of Generalize about the strength of ionic bonds based on the physical ionic bonds based on the physical properties of ionic compounds. properties of ionic compounds.

Categorize ionic bond formation Categorize ionic bond formation as exothermic or endothermic.as exothermic or endothermic.

Ionic BondIonic Bond

Ionic Bond Ionic Bond is the electrostatic force is the electrostatic force that holds oppositely charged that holds oppositely charged particles together.particles together.

Ionic Compound Ionic Compound is a compound that is a compound that contains an ionic bond.contains an ionic bond.

Ionic bonds between metals and Ionic bonds between metals and oxygen are called oxygen are called oxidesoxides..

Most other ionic compounds are Most other ionic compounds are considered salts.considered salts.

Binary Ionic Binary Ionic CompoundCompound

Binary Ionic compound Binary Ionic compound is an ionic is an ionic compound that contains two compound that contains two different elements.different elements.

One metallic cation and a One metallic cation and a nonmetallic anion.nonmetallic anion.

Examples: NaCl, MgO, KBr, LiFExamples: NaCl, MgO, KBr, LiF

Ionic Bond Ionic Bond FormationFormation

Electrons gained and lost in each Electrons gained and lost in each element must be equal. element must be equal. (conservation of electrons)(conservation of electrons)

Calcium and FluorineCalcium and Fluorine

Aluminum and OxygenAluminum and Oxygen

Sodium and ChlorineSodium and Chlorine

Properties of Properties of Ionic CompoundsIonic Compounds

Compounds are organized such that Compounds are organized such that a pattern repeats to balance a pattern repeats to balance attraction and repulsionattraction and repulsion

Total charge of a compound is Total charge of a compound is neutralneutral

Often highly organizedOften highly organized

Example: NaCl crystalExample: NaCl crystal

Crystal LatticeCrystal Lattice

A crystal lattice is a three A crystal lattice is a three dimensional geometric dimensional geometric arrangement of particles.arrangement of particles.

Each negative ion is surrounded Each negative ion is surrounded by a positive ion which results by a positive ion which results in strong attractions between in strong attractions between ions.ions.

Size and shape are dependent Size and shape are dependent on relative numbers of ions.on relative numbers of ions.

Crystal LatticeCrystal LatticePhysical Properties:Physical Properties:

Characteristics of bond strength Characteristics of bond strength – ionic bonds are relatively – ionic bonds are relatively strong and take a large amount strong and take a large amount of energy to break.of energy to break.

Melting point – highMelting point – high

Boiling point – highBoiling point – high

Hardness of material is high: Hardness of material is high: rigid and brittle solids.rigid and brittle solids.

Properties of Properties of Ionic CompoundsIonic Compounds

Crystal LatticeCrystal LatticeCharacteristics of the compound:Characteristics of the compound:

Conducts electricity, conditionallyConducts electricity, conditionally

Ions in solid state ionic compounds are locked Ions in solid state ionic compounds are locked in place and they do not have free electrons in place and they do not have free electrons in order to conduct electricity.in order to conduct electricity.

Ionic compounds that are melted or dissolved Ionic compounds that are melted or dissolved in aqueous solutions have ions that are free in aqueous solutions have ions that are free to move and therefore do conduct electricityto move and therefore do conduct electricity

Electrolyte – an ionic compound that Electrolyte – an ionic compound that conducts electricity in an aqueous solution.conducts electricity in an aqueous solution.

Energy and the Energy and the Ionic BondIonic Bond

Formation of ionic compounds forms Formation of ionic compounds forms a more stable system and therefore a more stable system and therefore reduces the energy required to reduces the energy required to sustain it.sustain it.

Since the creating of bonds lowers Since the creating of bonds lowers energy, energy is released in the energy, energy is released in the process. The creation of bonds is said to process. The creation of bonds is said to bebe Exothermic. Exothermic.

ExothermicExothermic – energy is released during – energy is released during a chemical reaction.a chemical reaction.

Energy and the Energy and the Ionic BondIonic Bond

Breaking of ionic compounds reduces Breaking of ionic compounds reduces the stability of a system and therefore the stability of a system and therefore increases the energy required to increases the energy required to sustain it .sustain it .

Since the creating of bonds lowers energy, Since the creating of bonds lowers energy, the breaking of bonds increases energy the breaking of bonds increases energy and therefore it is required for the process.and therefore it is required for the process.

EndothermicEndothermic – energy is absorbed during – energy is absorbed during a chemical reaction.a chemical reaction.

Lattice EnergyLattice EnergyLattice energy is the energy required to Lattice energy is the energy required to separate 1 mole of the ions of an ionic separate 1 mole of the ions of an ionic compound.compound.

higher the lattice energy the stronger the higher the lattice energy the stronger the bond strength.bond strength.

Directly related to the size of the ions bonded.Directly related to the size of the ions bonded.

smaller ions form compounds more closely smaller ions form compounds more closely because attraction increases with decreased because attraction increases with decreased distance.distance.

Also affected by charge of ionsAlso affected by charge of ionsHigher ion charge typically has higher lattice Higher ion charge typically has higher lattice energy.energy.

Practice ProblemsPractice ProblemsPage 217 #12-18 Page 217 #12-18

Names and Names and Formulas for Ionic Formulas for Ionic

CompoundsCompounds

Names and Names and Formulas for Ionic Formulas for Ionic

CompoundsCompounds Relate a formula unit of an ionic Relate a formula unit of an ionic compound to its composition.compound to its composition.

Write formulas for ionic Write formulas for ionic compounds and oxyanions.compounds and oxyanions.

Apply naming conventions to ionic Apply naming conventions to ionic compounds and oxyanions.compounds and oxyanions.

Formulas for Ionic Formulas for Ionic CompoundsCompounds

A standardized system for naming A standardized system for naming compounds was developed for compounds was developed for much the same reason as the SI much the same reason as the SI unit system. This serves as a unit system. This serves as a universal naming system for universal naming system for communication among the science communication among the science community. community.

Formula UnitFormula UnitA A formula unitformula unit is the chemical formula is the chemical formula for an ionic compound and represents for an ionic compound and represents the simplest ratio of ions.the simplest ratio of ions.

MgClMgCl22 not Mg not Mg44ClCl88

A A monoatomicmonoatomic ion is a one atom ion. ion is a one atom ion.

Oxidation numberOxidation number

Oxidation number Oxidation number (oxidation (oxidation state) the charge of a monatomic state) the charge of a monatomic ion.ion.

Formulas for Ionic Formulas for Ionic CompoundsCompounds

The symbol for the cation is The symbol for the cation is written first with the anion written first with the anion second.second.

Subscripts represent the number Subscripts represent the number of atoms of each element in a of atoms of each element in a compound.compound.

The total charge must equal zero The total charge must equal zero in an ionic compound.in an ionic compound.


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Polyatomic IonsPolyatomic IonsPolyatomic ions Polyatomic ions are made up of more than one are made up of more than one atom.atom.

Formulas for polyatomic ionic compoundsFormulas for polyatomic ionic compounds

Charge applies to the entire group of atoms.Charge applies to the entire group of atoms.

Parentheses are used if more than one Parentheses are used if more than one polyatomic ion is needed to balance a polyatomic ion is needed to balance a compound.compound.

Do not change subscripts within the ion Do not change subscripts within the ion groupgroup

Example (NHExample (NH44)O )O

Polyatomic IonsPolyatomic Ions

OxyanionOxyanion

An An oxyanionoxyanion is a polyatomic is a polyatomic negative ion composed of an negative ion composed of an element, usually a nonmetal, element, usually a nonmetal, bonded to one or more oxygen.bonded to one or more oxygen.

Oxyanion Naming Oxyanion Naming RulesRules

Names for Ions Names for Ions and Ionic and Ionic

CompoundsCompounds1.1. Name the cation followed by the Name the cation followed by the

anion.anion.

2.2. For monatomic cations, use the For monatomic cations, use the element name.element name.

3.3. For monatomic anions, use the For monatomic anions, use the root of the element with the suffix root of the element with the suffix –ide.–ide.

Names for Ions Names for Ions and Ionic and Ionic

CompoundsCompounds4.4. Multiple oxidation states are represented by a Multiple oxidation states are represented by a Roman numeral in paranthesis after the cation.Roman numeral in paranthesis after the cation.

a)a) This applies to transition metals with more This applies to transition metals with more than one oxidation state and not the Group 1 than one oxidation state and not the Group 1 and 2 cations.and 2 cations.

b)b) Example: FeO is Iron (II) oxide; FeExample: FeO is Iron (II) oxide; Fe22OO33 Iron (III) Iron (III) oxide.oxide.

5.5. With a polyatomic ion, name the cation With a polyatomic ion, name the cation followed by the name of the polyatomic ion.followed by the name of the polyatomic ion.

a)a) Example: NaOH is sodium hydroxide.Example: NaOH is sodium hydroxide.

Problem SolvingProblem Solving


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Metallic Bonds Metallic Bonds and the and the

Properties of Properties of MetalsMetals

Metallic Bonds Metallic Bonds and the and the

Properties of Properties of MetalsMetalsDescribeDescribe a metallic bond. a metallic bond.

RelateRelate the electron sea model to the electron sea model to the physical properties of metals.the physical properties of metals.

DefineDefine alloys, and categorize them alloys, and categorize them into two basic types.into two basic types.

MetalsMetals

Metals are not ionic but share Metals are not ionic but share several properties with ionic several properties with ionic compounds.compounds.

Metals also form lattices in the solid Metals also form lattices in the solid state, where 8 to 12 other atoms state, where 8 to 12 other atoms closely surround each metal atom.closely surround each metal atom.

Within the crowded lattice, the outer Within the crowded lattice, the outer energy levels of metal atoms overlap.energy levels of metal atoms overlap.

Electron Sea Electron Sea ModelModel

The electron sea model proposes that The electron sea model proposes that all metal atoms in a metallic solid all metal atoms in a metallic solid contribute their valence electrons contribute their valence electrons to form a "sea" of electron.to form a "sea" of electron.

• The electrons are free to move The electrons are free to move around and are referred to as around and are referred to as delocalized electrons, forming a delocalized electrons, forming a metallic cation.metallic cation.

Metallic BondsMetallic Bonds

A metallic bondA metallic bond is the attraction of is the attraction of an metallic cation for delocalized an metallic cation for delocalized electronselectrons


• Boiling points are much more Boiling points are much more extreme than melting points extreme than melting points because of the energy required to because of the energy required to separate atoms from the groups separate atoms from the groups of cations and electrons.of cations and electrons.


• Metals are malleable because they Metals are malleable because they can be hammered into sheets.can be hammered into sheets.

• Metals are ductile because they Metals are ductile because they can be drawn into wires.can be drawn into wires.


• Mobile electrons around cations Mobile electrons around cations make metals good conductors of make metals good conductors of electricity and heat.electricity and heat.

• As the number of delocalized As the number of delocalized electrons increases, so does electrons increases, so does hardness and strength.hardness and strength.

Metal AlloysMetal Alloys

An alloy is a mixture of elements An alloy is a mixture of elements that has metallic properties.that has metallic properties.

• The properties of alloys differ The properties of alloys differ from the elements they contain.from the elements they contain.


• SubstitutionalSubstitutional alloys are formed alloys are formed when some atoms in the original when some atoms in the original metallic solid are replaced by metallic solid are replaced by other metals of similar atomic other metals of similar atomic structure.structure.

• InterstitialInterstitial alloys are formed when alloys are formed when small holes in a metallic crystal small holes in a metallic crystal are filled with smaller atoms.are filled with smaller atoms.


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Study GuideStudy GuideKey ConceptsKey Concepts

Key ConceptsKey Concepts• A chemical bond is the force that A chemical bond is the force that

holds two atoms together.holds two atoms together.

• Some atoms form ions to gain Some atoms form ions to gain stability. This stable configuration stability. This stable configuration involves a complete outer energy involves a complete outer energy level, usually consisting of eight level, usually consisting of eight valence electrons.valence electrons.

• Ions are formed by the loss or gain of Ions are formed by the loss or gain of valence electrons.valence electrons.

Key ConceptsKey Concepts

• The number of protons remains The number of protons remains unchanged during ion formation.unchanged during ion formation.

• Ionic compounds contain ionic bonds Ionic compounds contain ionic bonds formed by the attraction of oppositely formed by the attraction of oppositely charged ions. charged ions.

• Ions in an ionic compound are Ions in an ionic compound are arranged in a repeating pattern arranged in a repeating pattern known as a crystal latticeknown as a crystal lattice

Key ConceptsKey Concepts• Ionic compound properties are Ionic compound properties are

related to ionic bond strength.related to ionic bond strength.

• Ionic compounds are electrolytes; Ionic compounds are electrolytes; they conduct an electric current in they conduct an electric current in the liquid phase and in aqueous the liquid phase and in aqueous solution.solution.

• Lattice energy is the energy needed Lattice energy is the energy needed to remove 1 mol of ions from its to remove 1 mol of ions from its crystal lattice. crystal lattice.

Key ConceptsKey Concepts• A formula unit gives the ratio of A formula unit gives the ratio of

cations to anions in the ionic cations to anions in the ionic compound.compound.

• A monatomic ion is formed from one A monatomic ion is formed from one atom. The charge of a monatomic ion atom. The charge of a monatomic ion is its oxidation number. is its oxidation number.

• Roman numerals indicate the Roman numerals indicate the oxidation number of cations having oxidation number of cations having multiple possible oxidation states. multiple possible oxidation states.

Key ConceptsKey Concepts• Polyatomic ions consist of more than Polyatomic ions consist of more than

one atom and act as a single unit. one atom and act as a single unit.

• To indicate more than one polyatomic To indicate more than one polyatomic ion in a chemical formula, place ion in a chemical formula, place parentheses around the polyatomic ion parentheses around the polyatomic ion and use a subscript. and use a subscript.

• A metallic bond forms when metal A metallic bond forms when metal cations attract freely moving, cations attract freely moving, delocalized valence electrons.delocalized valence electrons.

Key ConceptsKey Concepts• In the electron sea model, electrons In the electron sea model, electrons

move through the metallic crystal and move through the metallic crystal and are not held by any particular atom. are not held by any particular atom.

• The electron sea model explains the The electron sea model explains the physical properties of metallic solids. physical properties of metallic solids.

• Metal alloys are formed when a metal Metal alloys are formed when a metal is mixed with one or more other is mixed with one or more other elements.elements.

QuestionsQuestionsCations form when atoms _______ electrons. Cations form when atoms _______ electrons.

A.A. gain gain

B.B. lose lose

C.C. charge charge

D.D.delocalize delocalize

QuestionsQuestionsWhat is the repeating pattern of atoms in What is the repeating pattern of atoms in

an ionic solid called?an ionic solid called?

A.A. crystal lattice crystal lattice

B.B. ionic lattice ionic lattice

C.C. energy lattice energy lattice

D.D. ionic bonding ionic bonding

QuestionsQuestionsGive the name of the following: NaClOGive the name of the following: NaClO44

A.A. sodium hypochlorite sodium hypochlorite

B.B. sodium chlorite sodium chlorite

C.C. sodium chlorate sodium chlorate

D.D.sodium perchlorate sodium perchlorate

QuestionsQuestionsAs the distance between ions in an ionic As the distance between ions in an ionic

bond is shortened, bond is shortened,

A.A. the energy to break the bond decreases.the energy to break the bond decreases.

B.B. the electrostatic attraction decreases.the electrostatic attraction decreases.

C.C. the electrostatic attraction increases. the electrostatic attraction increases.

D.D. the ionic bond changes to a metallic the ionic bond changes to a metallic bond. bond.

QuestionsQuestionsAn alloy is what type of substance?An alloy is what type of substance?

A.A. heterogeneous mixture heterogeneous mixture

B.B. compound compound

C.C. mixture of elements mixture of elements

D.D.element element

QuestionsQuestionsWhich is NOT true about metallic solids?Which is NOT true about metallic solids?

A.A. Metals are shiny. Metals are shiny.

B.B. Metals are good conductors of heat and Metals are good conductors of heat and electricity. electricity.

C.C. Metals are ductile. Metals are ductile.

D.D.Metals have relatively low boiling Metals have relatively low boiling points. points.

QuestionsQuestionsElectrons in an atom’s outer most energy Electrons in an atom’s outer most energy

level are referred to as what?level are referred to as what?

A.A. ions ions

B.B. cations cations

C.C. valence electrons valence electrons

D.D.noble-gas electrons noble-gas electrons

QuestionsQuestionsWhat is the oxidation state of copper in What is the oxidation state of copper in

Cu(II)ClCu(II)Cl22? ?

A.A. 1+ 1+

B.B. 2+ 2+

C.C. 2– 2–

D.D.unable to determine unable to determine

QuestionsQuestionsWhich elements naturally occur with a full Which elements naturally occur with a full

octet of valence electrons? octet of valence electrons?

A.A. alkali metals alkali metals

B.B. alkali earth metals alkali earth metals

C.C. halogens halogens

D.D.noble gases noble gases

QuestionsQuestionsHow many electrons are in a full octet?How many electrons are in a full octet?

A.A. 10 10

B.B. 88

C.C. 66

D.D.4 4

The EndThe End

chem chapt 7

Documents

ionic compoundsdescribe

formation of ionic bonds

strength of ionic bonds

neutral ionic compounds

structure of ionic compounds

ionic compoundsionic

ionic bondionic bond

solid state ionic compounds