# Graphite and diamond are both giant covalent structures made entirely of carbon atoms, yet they have very different properties. Explain why graphite can conduct electricity but diamond cannot, and why graphite is soft whilst diamond is very hard.

> Eduqas GCSE Chemistry — C2 Bonding, structure and properties · Explain · 4 marks

## Mark scheme (4 marks)

1. In graphite, one electron from each carbon atom is delocalised (free to move), allowing it to carry charge / conduct electricity.
2. In diamond, all four outer electrons of each carbon atom are used in covalent bonds, so there are no delocalised electrons to carry charge / conduct electricity.
3. In graphite, there are no covalent bonds between the layers (only weak intermolecular forces), so the layers can slide over each other, making graphite soft.
4. In diamond, each carbon atom forms four covalent bonds in all directions, creating a rigid, giant covalent structure that makes diamond very hard.

## Key terms

- [giant covalent structure](https://www.gradenine.co.uk/glossary/giant-covalent-structure)

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Source: [GradeNine](https://www.gradenine.co.uk/q/graphite-and-diamond-are-both-giant-b08a954c) · Published by Druglandscape Ltd.