# Magnesium oxide is an ionic compound. Explain how magnesium oxide is formed when magnesium reacts with oxygen, including how the ions achieve a stable electronic structure.

> Edexcel GCSE Chemistry (1CH0) — 1.5 Ionic bonding · Explain · 4 marks

> Magnesium (atomic number 12) reacts vigorously with oxygen to form magnesium oxide, an ionic compound used as a refractory material in furnaces.

## Mark scheme (4 marks)

1. Magnesium atom loses 2 electrons to form a Mg²⁺ ion
2. Oxygen atom gains 2 electrons to form an O²⁻ ion
3. Both ions achieve a full outer shell / stable electronic structure (like a noble gas)
4. The oppositely charged ions are held together by electrostatic attraction to form the ionic compound

## Key terms

- [ionic compound](https://www.gradenine.co.uk/glossary/ionic-compound)
- [ion](https://www.gradenine.co.uk/glossary/ion)
- [electronic structure](https://www.gradenine.co.uk/glossary/electronic-structure)

## 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)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/magnesium-oxide-is-an-ionic-compound-5c9b718e) · Published by Druglandscape Ltd.