Ionic Compounds Chapter 6 Section 4

Writing Formulas Nomenclature – the naming of compounds –Substances used to have common names Salt, sugar, soda ash, milk of magnesia –Increase in the number of compounds led to the need for a naming system Binary Compounds – composed of two pieces Ternary Compounds – composed of three elements

Ionic Compounds Formed between cations and anions Binary and Ternary compound naming: 1.Name the cation. 2.Name the anion. 3.If the cation can have multiple charges use a roman numeral to indicate the charge. Examples: CaS = FeCl 2 = NaOH = Calcium sulfide Iron (II) chloride Sodium hydroxide

Formula writing: 1.Know your ions (symbols and charges) 2.Write the cations symbol first 3.Write the anions symbol 4.Balance the charges so that the sum is zero 5.Use parenthesis only if more than one of the indicated polyatomic ion is needed.

Write the Following Formulas Examples: Lithium bromide Copper (II) oxide Sodium nitrate Ammonium sulfide Strontium acetate LiBr CuO NaNO 3 (NH 4 ) 2 S Sr(C 2 H 3 O 2 ) 2

Changing the Suffix and Prefix The suffix and/or prefix of a polyatomic ion must be changed to reflect a difference in the number of oxygen atoms from the base ion.  1 less oxygen = -ite  2 less oxygens = Hypo- -ite  1 more oxygen = per- See the common ion sheet for examples.