The table shows data for four ionic compounds.
| Compound | Ions present | Relative formula mass | Melting point (∘C^\circ\mathrm{C}∘C) |
|---|---|---|---|
| sodium fluoride | Na+\mathrm{Na^{+}}Na+ and F−\mathrm{F^{-}}F− | 42 | 993 |
| sodium chloride | Na+\mathrm{Na^{+}}Na+ and Cl−\mathrm{Cl^{-}}Cl− | 58.5 | 801 |
| magnesium oxide | Mg2+\mathrm{Mg^{2+}}Mg2+ and O2−\mathrm{O^{2-}}O2− | 40 | 2852 |
| calcium oxide | Ca2+\mathrm{Ca^{2+}}Ca2+ and O2−\mathrm{O^{2-}}O2− | 56 | 2613 |
Which conclusion is supported by all of the data in the table?
The melting point depends only on which metal ion the compound contains
Compounds whose ions have higher charges have higher melting points
The melting point increases as the relative formula mass increases
The compounds with the highest melting points contain covalent bonds
56 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.