# Explain why elements in Group 1 of the periodic table become more reactive as you go down the group.

> Edexcel A-Level Chemistry (9CH0) — 1.2 Periodic table and trends · Explain · 5 marks

> Group 1 elements are known as the alkali metals. They all react with water, but the vigour of the reaction increases from lithium at the top to caesium at the bottom of the group.

## Mark scheme (5 marks)

1. All Group 1 atoms have one electron in their outer shell
2. Going down the group, the atoms get larger / have more electron shells
3. The outer electron is further from the nucleus going down the group
4. The attraction between the nucleus and the outer electron decreases / the outer electron is more easily lost
5. Because the outer electron is lost more easily, the element is more reactive (links electron loss to increased reactivity)

## Key terms

- [Group 1](https://www.gradenine.co.uk/glossary/group-1)

## Related

- [Revision notes for Edexcel A-Level Chemistry (9CH0)](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/explain-why-elements-in-group-1-835bd58e) · Published by Druglandscape Ltd.