# Sodium chloride is an ionic compound formed when sodium reacts with chlorine. Explain how an ionic bond forms between a sodium atom and a chlorine atom, and describe the structure of the ionic compound that results.

> OCR A-Level Chemistry B: Salters (H433) — 2.1 Atoms, compounds, molecules and equations · Explain · 5 marks

> Sodium is a metal in Group 1 of the periodic table. Chlorine is a non-metal in Group 7 of the periodic table. When sodium reacts with chlorine, sodium chloride is formed.

## Mark scheme (5 marks)

1. Sodium loses one electron (to form a positively charged ion / Na⁺)
2. Chlorine gains that electron (to form a negatively charged ion / Cl⁻)
3. An ionic bond is formed between the oppositely charged ions (Na⁺ and Cl⁻)
4. The ionic compound is held together by strong electrostatic forces (of attraction between oppositely charged ions)
5. Sodium chloride exists as a giant ionic structure / lattice (with many ions arranged in a regular pattern)

## Key terms

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

## Related

- [Revision notes for OCR A-Level Chemistry B: Salters (H433)](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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