Which formula represents a compound that contains three different elements?
CaCl2\text{CaCl}_2CaCl2
NH3\text{NH}_3NH3
H2O\text{H}_2\text{O}H2O
NaNO3\text{NaNO}_3NaNO3
93 exam-style questions on AQA GCSE Chemistry 1.1 A simple model of the atom, symbols, relative atomic mass, electronic charge and isotopes, covering 1.1.1a Atoms, elements and compounds, 1.1.1b Half equations and ionic equations, 1.1.2 Mixtures, 1.1.3 The development of the model of the atom (common content with physics), 1.1.4 Relative electrical charges of subatomic particles, 1.1.5 Size and mass of atoms, 1.1.6 Relative atomic mass, and 1.1.7 Electronic structure. Each one has a worked solution and a mark scheme showing where the marks go.