# Lithium, sodium and potassium are all elements in Group 1 of the periodic table. Explain why these three elements have similar chemical properties, and why their reactivity increases going down the group.

> Eduqas A-Level Chemistry — 2.2 Group 1, 2 and 7 · Explain · 5 marks

## Mark scheme (5 marks)

1. Elements in the same group have the same number of electrons in their outer shell
2. This gives them similar chemical properties
3. Going down the group, each element has more electron shells
4. The outer electron is held less strongly by the nucleus / is more easily lost
5. Therefore reactivity increases down the group because the outer electron is lost more readily

## Key terms

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

## Related

- [Revision notes for Eduqas A-Level Chemistry](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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Source: [GradeNine](https://www.gradenine.co.uk/q/lithium-sodium-and-potassium-are-all-9c7f47aa) · Published by Druglandscape Ltd.