A student places a clean strip of magnesium in blue copper(II) sulfate solution. The figure shows the strip after five minutes.
Figure: A strip of magnesium after five minutes in copper(II) sulfate solution

Name the brown coating that forms on the magnesium.
Write the ionic equation for the reaction between the magnesium and the copper ions.
Write the half equation for the oxidation that takes place.
Explain why the sulfate ions are not shown in the ionic equation.
39 exam-style questions on AQA GCSE Chemistry 4.1 Reactivity of metals, covering 4.1.1 Metal oxides, 4.1.2 The reactivity series, 4.1.3 Extraction of metals and reduction, and 4.1.4 Oxidation and reduction in terms of electrons. Each one has a worked solution and a mark scheme showing where the marks go.