# Sodium, potassium and lithium are all elements in Group 1 of the periodic table. Explain why these elements become more reactive going down the group.

> WJEC A-Level Chemistry (Wales) — 2.2 Group 1, 2 and 7 · Explain · 5 marks

> Group 1 metals all react vigorously with water to produce a metal hydroxide and hydrogen gas. Lithium reacts steadily, sodium reacts rapidly, and potassium reacts so vigorously that the hydrogen gas produced ignites.

## Mark scheme (5 marks)

1. Going down Group 1, the atoms have more electron shells
2. The outer electron is further from the nucleus going down the group
3. The attraction between the nucleus and the outer electron decreases going down the group
4. The outer electron is lost more easily going down the group
5. Because Group 1 metals react by losing their outer electron, the ease of losing this electron determines reactivity — so reactivity increases down the group

## Key terms

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

## Related

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Source: [GradeNine](https://www.gradenine.co.uk/q/sodium-potassium-and-lithium-are-all-10365e64) · Published by Druglandscape Ltd.