# Calcium fluoride is an ionic compound containing calcium ions and fluoride ions. Describe how a calcium atom and two fluorine atoms form ions, and explain what holds the ions together in calcium fluoride.

> Cambridge International IGCSE Chemistry (0620) — 2.4 Ions and ionic bonds · Describe and Explain · 4 marks

## Mark scheme (4 marks)

1. Calcium atom loses two electrons (to form a 2+ ion)
2. Each fluorine atom gains one electron (to form a fluoride/F⁻ ion)
3. The ions formed have full outer electron shells / achieve a stable noble gas configuration
4. Oppositely charged ions attract each other / electrostatic attraction between Ca²⁺ and F⁻ ions holds them together

## Key terms

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

## Related

- [Revision notes for Cambridge International IGCSE Chemistry (0620)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe and 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/calcium-fluoride-is-an-ionic-compound-89f56598) · Published by Druglandscape Ltd.