# Water is a molecule made up of hydrogen and oxygen atoms. Explain why water is a molecule and not a compound made of ions, and describe the type of bonding present in water and how it forms.

> OCR A-Level Chemistry A (H432) — 2.1 Atoms, compounds, molecules and equations · Explain · 5 marks

> Water (H₂O) is essential for life. Chemists classify water as a covalent molecule rather than an ionic compound. Water has a low boiling point compared to many ionic compounds such as magnesium oxide.

## Mark scheme (5 marks)

1. Water is made up of non-metal atoms only (hydrogen and oxygen are both non-metals)
2. The bond in water is a covalent bond
3. A covalent bond is a shared pair of electrons between two non-metals
4. Ionic compounds form when a metal loses electrons to a non-metal, forming oppositely charged ions — this does not happen in water
5. Water has a low boiling point because intermolecular forces between water molecules are weak / weaker than the electrostatic forces in ionic compounds

## Key terms

- [molecule](https://www.gradenine.co.uk/glossary/molecule)

## Related

- [Revision notes for OCR A-Level Chemistry A (H432)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/water-is-a-molecule-made-up-8f5c3446) · Published by Druglandscape Ltd.