1. IC5.5.5 Formulae of salts © Oxford University Press 2011 Formulae of salts How to work out the formulae of salts

2. IC5.5.5 Formulae of salts © Oxford University Press 2011 Salts are ionic compounds containing positive and negative ions. Overall the compound has no charge. The positive and negative charges of the ions in the formula balance. sodium ion Na + chloride ion Cl - + sodium chloride NaCl - + -

3. IC5.5.5 Formulae of salts © Oxford University Press 2011 What is the formula for copper(II) hydroxide? Cu(OH) 2 Copper(II) hydroxide copper ion Cu 2+ hydroxide ion OH - 2+ - --

4. IC5.5.5 Formulae of salts © Oxford University Press 2011 What is the formula for magnesium chloride? MgCl 2 magnesium chloride magnesium ion Mg 2+ chloride ion Cl - 2+ - --

5. IC5.5.5 Formulae of salts © Oxford University Press 2011 What is the formula for calcium sulfate? CaSO 4 calcium sulfate calcium ion Ca 2+ sulfate ion SO 4 2- 2- 2+ 2-

6. IC5.5.5 Formulae of salts © Oxford University Press 2011 What is the formula for calcium carbonate? CaCO 3 calcium carbonate calcium ion Ca 2+ carbonate ion CO 3 2- 2- 2+ 2-

7. IC5.5.5 Formulae of salts © Oxford University Press 2011 What is the formula for iron(III) oxide? Fe 2 O 3 iron(III) oxide iron ion Fe 3+ oxide ion O 2- 3+ 2- 3+ 2-