III. Ionic Compounds (p. 176 – 180, 203 – 211) Ch. 6 & 7 - Chemical Bonding III. Ionic Compounds (p. 176 – 180, 203 – 211)

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!

C. Ionic Nomenclature Common Ion Charges 1+ 2+ 3+ NA 3- 2- 1-

C. Ionic Nomenclature Writing Ionic Formulas: Calcium chloride Ca2+ Cl1- charges do not cancel, must criss-cross charges Rewrite as complete formula without oxidation numbers CaCl2 1 2

C. Ionic Nomenclature potassium chloride magnesium nitrate copper(II) chloride K+ Cl-  KCl Mg2+ NO3-  Mg(NO3)2 Cu2+ Cl-  CuCl2

C. Ionic Formulas calcium oxide aluminum chlorate Ca2+ O2-  CaO magnesium chloride Ca2+ O2-  CaO Al3+ ClO3-  Al(ClO3)3 Mg2+ Cl-  MgCl2

C. Ionic Nomenclature NaBr Na2CO3 sodium bromide FeCl3 sodium carbonate iron(III) chloride

D. Ionic Compounds with Transition Metals For transition metals, valence electrons and oxidation #’s are variable Exceptions: Sn (tin), Pb (lead), and Ag1+, Zn2+, Cd2+ 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 Chromium (III) oxide 3 x -2 = -6 2 x ___ = +6 -3 Chromium (II) oxide 2 x -2 = -4 2 x ___ = +4 +2

E. Ionic Formulas with Transition Metals Copper (II) bromide Tin (IV) oxide Manganese (II) chloride Cu2+ + Br -  CuBr2 Sn4+ + O2-  Sn2O4  SnO2 Mn2+ + Cl -  MnCl2

E. Ionic Names with Transition Metals Cr2(SO4)3 HgO FeCl3 Chromium (III) sulfate Mercury (II) oxide iron(III) chloride