The table shows data about four chlorides.
| Chloride | Melting point in °C | Boiling point in °C | Conducts when molten? |
|---|---|---|---|
| sodium chloride, NaCl | 801 | 1413 | yes |
| magnesium chloride, MgCl2\mathrm{MgCl_{2}}MgCl2 | 714 | 1412 | yes |
| silicon chloride, SiCl4\mathrm{SiCl_{4}}SiCl4 | −69 | 58 | no |
| phosphorus chloride, PCl3\mathrm{PCl_{3}}PCl3 | −94 | 76 | no |
Explain why the melting point of magnesium chloride is much higher than the melting point of silicon chloride.
Explain why molten silicon chloride does not conduct electricity.
A student writes: "Silicon chloride has a low melting point because the covalent bonds in silicon chloride are weak." Evaluate the student's statement.
Determine the physical states of silicon chloride and phosphorus chloride at 65 °C.
Aluminium chloride is made from a metal and a non-metal. At atmospheric pressure it turns directly into a gas at 180 °C. When it is melted under pressure, it conducts electricity only very poorly.
Suggest what these data show about the structure and bonding in aluminium chloride. Justify your answer.
48 exam-style questions on Edexcel GCSE Chemistry 2.5 Types of substance, covering 2.5.1 Classifying substances by structure and bonding, 2.5.2 Properties of ionic and simple molecular substances, 2.5.3 Giant covalent structures: diamond and graphite, 2.5.4 Fullerenes, graphene and simple polymers, 2.5.5 Properties of metals and non-metals, and 2.5.6 Limitations of bonding models and representations. Each one has a worked solution and a mark scheme showing where the marks go.