# Describe how a covalent bond is formed between two non-metal atoms and explain why simple molecular substances such as hydrogen chloride have low boiling points.

> AQA GCSE Chemistry (8462) — 4.2.1 Chemical bonds, ionic, covalent and metallic · Describe and Explain · 4 marks

## Mark scheme (4 marks)

1. A covalent bond is formed by the sharing of a pair of electrons (between two non-metal atoms).
2. The shared electrons hold the two atoms together (strong bond within the molecule).
3. There are only weak intermolecular forces between the molecules.
4. Little energy is needed to overcome these weak intermolecular forces, so the boiling point is low.

## Key terms

- [covalent bond](https://www.gradenine.co.uk/glossary/covalent-bond)
- [simple molecular substance](https://www.gradenine.co.uk/glossary/simple-molecular-substance)

## Related

- [Revision notes for AQA GCSE Chemistry (8462)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe and Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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Source: [GradeNine](https://www.gradenine.co.uk/q/describe-how-a-covalent-bond-is-3d2817cc) · Published by Druglandscape Ltd.