# Explain why graphite can conduct electricity but diamond cannot, even though both substances are forms of carbon.

> Edexcel GCSE Chemistry (1CH0) — 1.7 Types of substance · Explain · 4 marks

> Graphite and diamond are both giant covalent structures made entirely of carbon atoms, yet they have very different electrical properties.

## Mark scheme (4 marks)

1. In graphite, each carbon atom forms bonds with only three other carbon atoms (leaving one electron not used in bonding)
2. Graphite has delocalised electrons that are free to move through the structure
3. These delocalised electrons carry charge through graphite, allowing it to conduct electricity
4. In diamond, each carbon atom forms four covalent bonds so all electrons are used in bonding / there are no free or delocalised electrons in diamond

## Related

- [Revision notes for Edexcel GCSE Chemistry (1CH0)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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