Chapter 7: Compounds and Their Bonds Ionic Compounds Naming Ionic Formulas

Ionic Compounds Attraction between + ions and - ions Electrons go from metals to nonmetals electron transfer metal nonmetal ion + ion – Electrons lost = Electrons gain

Formulas of Ionic Compounds Formulas of ionic compounds are determined from the charges on the ions atoms ions     – Na  +  F :  Na + : F :  NaF     sodium fluorine sodium fluoride formula Charge balance: = 0

Writing a Formula Write the formula for the ionic compound that will form between Ba 2+ and Cl . Solution: 1. Balance charge with + and – ions 2. Write the positive ion of metal first, and the negative ion Ba 2+ Cl  Cl  3. Write the number of ions needed as subscripts BaCl 2

Learning Check Write the correct formula for the compounds containing the following ions: A. Na +, S 2- 1) NaS 2) Na 2 S3) NaS 2 B. Al 3+, Cl - 1) AlCl 3 2) AlCl 3) Al 3 Cl C. Mg 2+, N 3- 1) MgN 2) Mg 2 N 3 3) Mg 3 N 2

Solution A. Na +, S 2- 2) Na 2 S B. Al 3+, Cl - 1) AlCl 3 C. Mg 2+, N 3- 3) Mg 3 N 2

Naming Binary Ionic Compounds Contain 2 different elements Name the metal first, then the nonmetal as -ide. Use name of a metal with a fixed charge Groups 1A, 2A, 3A and Ag, Zn, and Cd Examples: NaClsodium chloride ZnI 2 zinc iodide Al 2 O 3 aluminum oxide

Learning Check Complete the names of the following binary compounds: Na 3 Nsodium ________________ KBrpotassium________________ Al 2 O 3 aluminum ________________ MgS_________________________

Solution Complete the names of the following binary compounds: Na 3 Nsodium nitride KBrpotassium bromide Al 2 O 3 aluminum oxide MgSmagnesium sulfide

Transition Metals Many form 2 or more positive ions or or 3+ Ag + Cd 2+ Cu +, Cu 2+ Fe 2+, Fe 3+ silver cadmium copper(I) ion iron(II) ion ion ion copper (II) ion iron(III) ion Zn 2+ zinc ion

Learning Check A. The formula for the ionic compound of Na + and O 2- is 1) NaO2) Na 2 O3) NaO 2 B. The formula of a compound of aluminum and chlorine is 1) Al 3 Cl2) AlCl 2 3) AlCl 3 C. The formula of Fe 3+ and O 2- is 1) Fe 3 O 2 2) FeO 3 3) Fe 2 O 3

Solution A. The formula for the ionic compound of Na + and O 2- is 2) Na 2 O B. The formula of a compound of aluminum and chlorine is 3) AlCl 3 C. The formula of Fe 3+ and O 2- is 3) Fe 2 O 3

Names of Variable Ions Use a roman number after the name of a metal that forms two or more ions Transition metals and the metals in groups 4A and 5A FeCl 3 (Fe 3+ ) iron (III) chloride CuCl (Cu + ) copper (I) chloride SnF 4 (Sn 4+ ) tin (IV) fluoride PbCl 2 (Pb 2+ )lead (II) chloride Fe 2 S 3 (Fe 3+ )iron (III) sulfide

Learning Check Complete the names of the following binary compounds with variable metal ions: FeBr 2 iron (_____) bromide Cu 2 Ocopper (_____) oxide SnCl 4 ___(_____ ) ______________ Fe 2 O 3 ________________________ CuS________________________

Solution Complete the names of the following binary compounds with variable metal ions: FeBr 2 iron ( II ) bromide Cu 2 Ocopper ( I ) oxide SnCl 4 tin (IV) chloride Fe 2 O 3 iron (III) oxide CuScopper (II) sulfide

Learning Check Name the following compounds: A. CaO 1) calcium oxide2) calcium(I) oxide 3) calcium (II) oxide B. SnCl 4 1) tin tetrachloride2) tin(II) chloride 3) tin(IV) chloride C. Co 2 O 3 1) cobalt oxide 2) cobalt (III) oxide 3) cobalt trioxide

Solution Name the following compounds: A. CaO1) calcium oxide B. SnCl 4 3) tin(IV) chloride C.Co 2 O 3 2) cobalt (III) oxide

Polyatomic Ions Easy to remember –P-As-Se- = all 3- charge, all O 4 attached PO Name Phosphate –S = O 4 attached, but a charge of 2- SO 4 - Name Sulfate –Halogens = all O 3, charge of 1- ClO 3 - Name Chlorate –Transition Metals = Very in charges - will be told 2 to remember –Carbonate – CO 3 2- –Nitrate – NO 3 1-

Polyatomic Naming Changes to the number of Oxygen changes the name Example = ClO 3 - Chlorate Gain an oxygen = ClO 4 Name changes from – Chlorate to perchlorate Lose an oxygen = ClO 2 –Name changes from – Chlorate to Chlorite Lose two oxygens = ClO 1 –Name changes from – sulfate to hypochlorite

Naming Polyatomics Remember - # of Oxygens PO 4 – Phosphate (base polyatomic) Gain an Oxygen PO 5 - perphosphate PO 3 - phosphite PO 2 - hyperphosphite Loss 2 Oxygens Loss 1 Oxygens