Formulae

1 State the formulae of the elements and compounds named in the subject content

2 Define the molecular formula of a compound as the number and type of different atoms in one molecule

5 Define the empirical formula of a compound as the simplest whole number ratio of the different atoms or ions in a compound

3 Deduce the formula of a simple compound from the relative numbers of atoms present in a model or a diagrammatic representation

6 Deduce the formula of an ionic compound from the relative numbers of the ions present in a model or a diagrammatic representation or from the charges on the ions

4 Construct word equations and symbol equations to show how reactants form products, including state symbols