Nomenclature Rules for naming compounds

Alkali & alkaline earth metals For metals of Groups 1 & 2, write the metal’s name as it appears on the periodic table – Sodium, Potassium, Magnesium, Calcium …. Change the ending of the nonmetal to “-ide” o Carbide o Nitride, phosphide o Oxide, sulfide o Fluoride

Transition metals’ compounds Stock Method When metal has more than one oxidation #, one designates the metal’s charge with a Roman numeral in parentheses behind the metal’s name – Copper (I) chloride = CuCl – Copper (II) chloride = CuCl 2 The nonmetal’s ending is changed to “-ide”

Determining metals’ charges One examines the total charge of the anion – Using the octet rule, find # of electrons needed for nonmetal to achieve noble gas’ stable outer 8 e - – Group 15 = - 3; Group 16 = - 2; Group 17 = - 1 – Multiply anion’s negative charge by its # subscript Fe 2 O 3 : Oxygen has charge of - 2. O 3 = (3)( - 2) = - 6 total One balances this negative charge with the transition metal’s positive charge O 3 = - 6 Fe 2 = + 6; + 6/ 2 Fe = + 3 per Fe Iron (III) chloride

Exceptions in the d block Zinc [Zn] always has oxidation # of 2+ Cadmium [Cd] always has oxidation # of 2+ Silver [Ag] always has oxidation # of 1+ These NEVER use a Roman Numeral designator when naming their compounds – AgCl = silver chloride – ZnCl 2 = zinc chloride – CdCl 2 = cadmium chloride

Two Nonmetals Because nonmetals can share their electrons in numerous ways, one designates their subscripts in a chemical formula with prefixes 1 = mono- (only for 2 nd one)2 = di- 3 = tri-4 = tetra- 5 = penta-6 = hexa- 7 = hepta-8 = octa- 9 = nona-10 = de See Modern Chemistry, p 228

Examples of 2 Nonmetals CCl 4 = carbon tetrachloride NO = nitrogen monoxide N 2 O 5 = dinitrogen pentoxide CO 2 = carbon dioxide P 4 O 10 = tetraphosphorus decoxide P 2 S 3 = diphosphorus trisulfide NOTE: 1] Never start name with “mono-” 2] Drop “a/o” on prefix if double vowels sound bad

Binary Molecular Compounds Covalent Network compounds may also use system of prefixes – Si 3 N 4 = trisilicon tetranitride Metals right of the d block may also use Stock method (Roman numerals) OR prefixes – PbO 2 = lead (IV) oxide OR lead dioxide Transition metals may also use the system of prefixes in their nomenclature – Mo 2 O 3 = molybdenum (III) oxide = dimolybdenum trioxide

Polyatomic Ions Atoms themselves are covalently bound to each other As a GROUP, they have an ionic charge – These oxidation numbers never change. – These oxidation numbers must be memorized! They form ionic compounds When the # of oxygens change, so do their prefixes and suffixes

Those with oxidation # of 1 - AcetateCH 3 COO - BicarbonateHCO 3 - (hydrogen carbonate) BromateBrO 3 - Perchlorate ClO 4 - ChlorateClO 3 - Chlorite ClO 2 - CyanideCN - Hypochlorite ClO - HydroxideOH - NitrateNO 3 - Nitrite NO 2 - Permanganate MnO 4 -

Polyatomic Ions of 2 - charge CarbonateCO 3 = ChromateCrO 4 = DichromateCr 2 O 7 = OxalateC 2 O 4 = PeroxideO 2 = SulfateSO 4 = SulfiteSO 3 =