# Potassium iodide is an ionic compound. Describe how a potassium atom and an iodine atom form a potassium ion and an iodide ion, and state the type of bond that holds these ions together in the solid compound.

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

## Mark scheme (4 marks)

1. Potassium atom loses one electron (to form a positive ion / potassium ion with a 1+ charge)
2. Iodine atom gains one electron (to form a negative ion / iodide ion with a 1− charge)
3. Both ions achieve a stable (full outer shell / noble gas) electron configuration
4. The ions are held together by an ionic bond / electrostatic attraction between oppositely charged ions

## Key terms

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

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Source: [GradeNine](https://www.gradenine.co.uk/q/potassium-iodide-is-an-ionic-compound-7306995e) · Published by Druglandscape Ltd.