3 Sets of Rules of Naming Rules Class or Type I - Ionic Bond between metal predictable + charge and a negative nonmetal or polyatomic ion ; name cations, anion ends in “ide” Examples: NaCl – sodium chloride ; MgCl2, magnesium chloride Class or Type II- Ionic Bond with variable oxidation state transition metal; Roman numerals used to specify charge of transition metal Example: CuCl2 – copper(II) chloride Class or Type III – Covalent bonds between Two nonmetals; uses prefixes Example: CO2 – carbon dioxide; N2O4 – dinitrogen tetroxide

Location of First Element in Formula determines class rules +1 Class or Type I +2 +3 Class or Type II Class or Type III +1 +2

Location of First Element in Formula determines class rules +1 Class or Type I +2 +3 Class or Type II Class or Type III +1 +2

Compare the charges of groups 1A,2A and 3A to 6B, 7B and 8B Compare the charges of groups 1A,2A and 3A to 6B, 7B and 8B. What is different?

Difference between Class I and II Compounds: Class I only 1 possible formula; Class II two or more possible formulas Sodium chloride Copper(II) Chloride is blue Only 1 compound possible NaCl Copper(I) chloride is green CuCl CuCl2

Charges of Class I vs Class II Cations CLASS I CATIONS CLASS II CATIONS Group 1 Group 2 Li +1 Na +1 Mg +2 K +1 Ca+2 Rb +1 Sr +2 Cs +1 Ba+2 Ag +1 Cd +2 Zn +2 Ga +3 In +3 Al +3

Rules for Naming Class II Compounds Metal cation first, negative ion second + Charge of metal in written in Roman Numerals in ( ) For neutral compound: sum of + = sum of – Final answer must be simplest ratio

Example Problems: Name CuCl and CuCl2 Example #1: CuCl: Cu = transition metal charge = ? Cl group 7 charge = -1; 1 Cl present in formula ? + 1 (-1) = 0 ; Copper(I) Chloride ? = +1

Example #2: Name CuCl2 CuCl2: Cu = transition metal charge = ? Cl group 7 charge = -1; 2 Cl present in formula ? + 2 (-1) = 0 ; Copper(II) Chloride ? = +2

Practice: Name the following compounds FeCl3 ? + 3(-1) = 0; ? = +3 iron(III) chloride CuSO4 Recall [SO4] -2 ; ? + 1(-2) = 0; ? = +2 Copper(II) sulfate

Practice: Name the following compounds Co3(PO4)2 Recall PO4-3 : - charge = 2(-3) = -6 ? + 2(-3) = 0; ? = +6; however . . . There are 3 cobalt ions, charge on each cobalt is +6/3 =+ 2 cobalt(II) phosphate

Class II compounds: Writing Formulas Charge on transition metal will be given in ( ) Use periodic table or polyatomic ion list to determine negative charge. Sum of charges must be zero. If + charge ≠ - charge, use “Criss-Cross” technique Final subscripts must be simplest ratio.

Class II Writing Formulas: Examples What is the formula of What is the formula of Iron(II) = Fe+2 O group 6 = O-2 Iron(III) = Fe+3 O group 6 = O-2 Fe+3O-2 → Fe2O3 Fe+2O-2 → FeO

Practice – what is the formula of tin(IV) oxide? Tin(IV) = Sn+4 Oxide = O-2 (group 6) Sn+4 O-2 Sn2O4 - not in simplest terms Final Ans: SnO2

Practice write formulas for each of the of following: nickel(II) phosphate Ans: Ni+2 PO4-3 Ni3(PO4)2 Manganese(II) nitrate Ans: Mn+2 NO3-1 Mn(NO3)2