Ionic Compounds

An ion is an atom or group of atoms that has either a + or − charge. An ionic compound: when a metal atom donates its valence electron(s) to a non-metal atom. – Metal atom (e - donor) becomes + ion (cation) – Non-metal atom (e - acceptor) becomes − ion (anion)

Properties of Ionic Compounds Hard, brittle solids Can form crystal lattices High melting point Soluble in water and forms electrolytes (able to conduct electricity)

Naming Ionic Compounds General Rule: 1.Name the metal ion 1 st (same name as element) 2.Name the non-metal ion 2 nd (ending becomes –ide) Eg. a) LiBrd) Na 3 P b) MgCl 2 e) BeS c) Al 2 O 3 lithium bromide aluminum oxide magnesium chloride sodium phosphide beryllium sulphide

Writing the Formulas 1.Write the symbols, with metal (on left) and non-metal (on right). 2.Write the ionic charges above the symbol. 3.Criss-cross the ionic charge #s 4.Reduce the chemical formula if necessary. **Note: If 1 is present, omit it in final answer**

Eg. a) magnesium bromideb) aluminum sulphide Try: c) potassium fluoride d) calcium phosphide

Multivalent Metals Some metals have multiple ionic charges. Roman numerals (eg. I, II, III, IV) are used to identify the charge for the metal ion. (p. 158) Eg. copper (1+ or 2+), nickel (2+ or 3+), lead (2+ or 4+) Try: a)titanium(IV) chloride b)cobalt(II) bromide c)Cu 2 O d)Ni 3 P 2