# Group 1 metals react with water. Describe what you would observe when a small piece of potassium is placed on water, and explain why potassium reacts more vigorously than lithium.

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

> Group 1 of the periodic table contains lithium, sodium and potassium. All of these metals react with cold water, producing a metal hydroxide and hydrogen gas.

## Mark scheme (5 marks)

1. Potassium moves/floats on the surface of the water
2. Potassium catches fire / burns with a lilac/violet flame
3. Effervescence / bubbles of gas are produced (hydrogen gas given off)
4. Potassium has more electron shells than lithium / potassium's outer electron is further from the nucleus
5. The outer electron in potassium is lost more easily than in lithium, so potassium reacts more vigorously

## Key terms

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

## Related

- [Revision notes for Eduqas A-Level Chemistry](https://www.gradenine.co.uk/learn)
- [How to answer "Describe and Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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Source: [GradeNine](https://www.gradenine.co.uk/q/group-1-metals-react-with-water-9db8b852) · Published by Druglandscape Ltd.