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 ; MgCl 2, magnesium chloride Class or Type II- Ionic Bond with variable oxidation state transition metal; Roman numerals used to specify charge of transition metal Example: CuCl 2 – copper(II) chloride Class or Type III – Covalent bonds between Two nonmetals; uses prefixes Example: CO 2 – carbon dioxide; N 2 O 4 – dinitrogen tetroxide

Location of First Element in Formula determines class rules Class or Type I Class or Type II Class or Type III

Location of First Element in Formula determines class rules Class or Type I Class or Type II Class or Type III

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

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

Difference between Class I and II Compounds: Class I only 1 possible formula; Class II two or more possible formulas Sodium chloride Only 1 compound possible NaCl Copper(II) Chloride is blue Copper(I) chloride is green CuCl 2 CuCl

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 CuCl 2 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 CuCl 2 CuCl 2 : 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 FeCl 3 ? + 3(-1) = 0; ? = +3 iron(III) chloride CuSO 4 Recall [SO 4 ] -2 ; ? + 1(-2) = 0; ? = +2 Copper(II) sulfate

Practice: Name the following compounds Co 3 (PO 4 ) 2 Recall PO 4 -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 Iron(II) = Fe +2 O group 6 = O -2 What is the formula of Iron(III) = Fe +3 O group 6 = O -2 Fe +2 O -2 → FeO Fe +3 O -2 → Fe 2 O 3

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

Practice write formulas for each of the of following: nickel(II) phosphate Ans: Ni +2 PO 4 -3 Ni 3 (PO 4 ) 2 Manganese(II) nitrate Ans: Mn +2 NO 3 -1 Mn(NO 3 ) 2