# Calcium chloride is an ionic compound used to de-ice roads in winter. Explain how an ionic bond forms when calcium reacts with chlorine to produce calcium chloride.

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

> Calcium is a Group 2 metal. Chlorine is a Group 7 non-metal. When they react, each calcium atom reacts with two chlorine atoms to form one formula unit of calcium chloride, CaCl₂.

## Mark scheme (5 marks)

1. Calcium loses two electrons (from its outer shell)
2. Each chlorine atom gains one electron (into its outer shell)
3. Calcium forms a 2+ ion (positively charged ion)
4. Each chlorine forms a 1− ion (negatively charged ion)
5. The oppositely charged ions are held together by strong electrostatic forces (forming an ionic bond)

## 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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Source: [GradeNine](https://www.gradenine.co.uk/q/calcium-chloride-is-an-ionic-compound-9386f6eb) · Published by Druglandscape Ltd.