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

> AQA A-Level Chemistry (7405) — 3.2.1 Periodicity · 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 to caesium.

## Mark scheme (5 marks)

1. Group 1 atoms react by losing one outer electron
2. As you go down the group, the atoms have more electron shells / the outer electron is further from the nucleus
3. There is increased shielding / more inner electrons shield the outer electron from the nucleus
4. The electrostatic attraction between the nucleus and the outer electron decreases
5. Therefore the outer electron is lost more easily, making the atom more reactive

## Key terms

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

## Related

- [Revision notes for AQA A-Level Chemistry (7405)](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)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/explain-why-elements-in-group-1-1b3428b1) · Published by Druglandscape Ltd.