Diamond and graphite are both made only of carbon atoms, but they have very different properties.
The table shows some data for diamond and graphite.
| Property | Diamond | Graphite |
|---|---|---|
| hardness | hardest natural substance | soft, layers flake off easily |
| electrical conductivity | does not conduct | good conductor |
| melting point in °C | above 3500 | above 3600 |
| density in g cm−3\mathrm{g\,cm^{-3}}gcm−3 | 3.51 | 2.26 |
Explain the similarities and differences in the hardness, electrical conductivity and melting points of diamond and graphite, in terms of their structure and bonding.
Silicon carbide, SiC, has a structure similar to diamond. Each silicon atom is covalently bonded to four carbon atoms and each carbon atom is covalently bonded to four silicon atoms. Predict two properties of silicon carbide. Explain your predictions.
Suggest why graphite has a lower density than diamond.
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.