# Sodium chloride is an ionic compound. Explain how sodium chloride is formed from its elements, and why it has a high melting point.

> Edexcel A-Level Chemistry (9CH0) — 2.1 Ionic bonding · 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 they react together, they form the ionic compound sodium chloride.

## Mark scheme (5 marks)

1. Sodium loses one electron (to form a positive ion / Na⁺)
2. Chlorine gains one electron (to form a negative ion / Cl⁻)
3. Both ions achieve a full outer shell / stable electronic configuration
4. Sodium chloride forms a giant ionic lattice in which there are strong electrostatic forces of attraction between oppositely charged ions
5. A large amount of energy is needed to overcome these strong electrostatic forces, so the melting point is high

## Related

- [Revision notes for Edexcel A-Level Chemistry (9CH0)](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)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/sodium-chloride-is-an-ionic-compound-2c9d7011) · Published by Druglandscape Ltd.