I II III IV

III. Ionic Compounds(p. 176 – 180, 203 – 211)

Ch. 6 & 7 - Chemical Bonding

Formula Unit

A. Energy of Bond Formation

Lattice Energy Energy released when one

mole of an ionic crystalline compound is formed from gaseous ions

B. Lewis Structures

Covalent – show sharing of e-

Ionic – show transfer of e-

B. Lewis Structures

Covalent – show sharing of e-

Ionic – show transfer of e-

C. Ionic Nomenclature

Ionic Formulas

Write each ion, cation first. Don’t show charges in the final formula.

Overall charge must equal zero. If charges cancel, just write symbols. If not, use subscripts to balance charges.

Use parentheses to show more than one polyatomic ion.

Stock System - Roman numerals indicate the ion’s charge.

C. Ionic Nomenclature

Ionic Names

Write the names of both ions, cation first.

Change ending of monatomic ions to -ide.

Polyatomic ions have special names.

Stock System - Use Roman numerals to show the ion’s charge if more than one is possible. Overall charge must equal zero.

C. Ionic Nomenclature

Consider the following: Does it contain a polyatomic ion?

-ide, 2 elements no-ate, -ite, 3+ elements yes

Does it contain a Roman numeral?Check the table for metals not in Groups 1 or 2.

No prefixes!

Common Ion Charges

1+

2+ 3+NA 3- 2- 1-

0

C. Ionic Nomenclature

C. Ionic Nomenclature

Writing Ionic Formulas:

Calcium chlorideCa2+ Cl1-

charges do not cancel, must criss-cross charges

Rewrite as complete formula without oxidation numbers

CaCl2

21

potassium chloride

magnesium nitrate

copper(II) chloride

K+ Cl

Mg2+ NO3

Cu2+ Cl

KCl

Mg(NO3)2

CuCl2

C. Ionic Nomenclature

calcium oxide

aluminum chlorate

magnesium chloride

Ca2+ O2 CaO

Al3+ ClO3 Al(ClO3)3

Mg2+ Cl MgCl2

C. Ionic Formulas

NaBr

Na2CO3

FeCl3

sodium bromide

sodium carbonate

iron(III) chloride

C. Ionic Nomenclature

D. Ionic Compounds with Transition Metals

For transition metals, valence electrons and oxidation #’s are variable

Exceptions: Sn (tin), Pb (lead), and AgSn (tin), Pb (lead), and Ag1+1+, , ZnZn2+2+, Cd, Cd2+2+

Roman numerals indicate the oxidation #

Chromium (III) = Cr3+

Iron (II) = Fe2+

Lead (IV) = Pb4+

E. Naming Ionic Compounds with Transition Metals

Write the ox. # in parentheses using Roman numerals. To determine oxidation #, know that overall charge of compound = 0

Cr2O3

CrO

3 x -2 = -6

2 x ___ = +6-3

Chromium (III) oxide

2 x -2 = -4

2 x ___ = +4+2

Chromium (II) oxide

Copper (II) bromide

Tin (IV) oxide

Manganese (II) chloride

Cu2+ + Br - CuBr2

Sn4+ + O2- Sn2O4 SnO2

Mn2+ + Cl - MnCl2

E. Ionic Formulas with Transition Metals

Cr2(SO4)3

HgO

FeCl3

Chromium (III) sulfate

Mercury (II) oxide

iron(III) chloride

E. Ionic Names with Transition Metals