Metal M reacts with chlorine to form an ionic compound with the formula MCl3\mathrm{MCl_3}MCl3.
A student writes the formula of the sulfate of metal M as M3(SO4)2\mathrm{M_3(SO_4)_2}M3(SO4)2.
Explain why the student's formula is incorrect and give the correct formula.
119 exam-style questions on Edexcel GCSE Chemistry 2.3 Ionic bonding, covering 2.3.1 Ions and the formation of ionic bonds, 2.3.2 Naming and deducing formulae of ionic compounds, and 2.3.3 Giant ionic lattices. Each one has a worked solution and a mark scheme showing where the marks go.