# Astatine is a halogen found below iodine in Group 7. Predict and explain the properties of astatine compared to iodine, including its reactivity and physical state at room temperature.

> Edexcel GCSE Chemistry (1CH0) — 6.2 Group 7 · Predict and explain · 4 marks

> Astatine is a very rare halogen at the bottom of Group 7. It is a radioactive element that is difficult to study, so scientists use trends in Group 7 to predict its properties.

## Mark scheme (4 marks)

1. Astatine is less reactive than iodine
2. Because astatine has more electron shells / the outer shell is further from the nucleus, so it is harder / less able to gain an electron
3. Astatine has a higher boiling point than iodine / is a solid at room temperature
4. Because boiling points increase down Group 7 / the trend in Group 7 is increasing boiling point going down the group

## Key terms

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

## Related

- [Revision notes for Edexcel GCSE Chemistry (1CH0)](https://www.gradenine.co.uk/learn)
- [How to answer "Predict and 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/astatine-is-a-halogen-found-below-5be159a5) · Published by Druglandscape Ltd.