A high-temperature test chamber uses a support to hold a temperature sensor. The support reaches 1400 ∘C1400\,^{\circ}\mathrm{C}1400∘C during use and must remain solid.
The support must be made from one of these ionic compounds.
| Compound | Ions present | Melting point (∘C^\circ\mathrm{C}∘C) |
|---|---|---|
| sodium bromide | Na+\mathrm{Na^{+}}Na+ and Br−\mathrm{Br^{-}}Br− | 747 |
| magnesium fluoride | Mg2+\mathrm{Mg^{2+}}Mg2+ and F−\mathrm{F^{-}}F− | 1263 |
| calcium oxide | Ca2+\mathrm{Ca^{2+}}Ca2+ and O2−\mathrm{O^{2-}}O2− | 2613 |
An engineer chooses magnesium fluoride because its positive ions have a larger charge than the positive ions in sodium bromide.
Evaluate the engineer's choice using all the data and ideas about ionic bonding.
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.