# Explain why elements in the same group of the periodic table have similar chemical properties, and why metallic character increases going down Group 1.

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

> The periodic table organises elements into groups and periods. Elements in the same group share similar chemical properties, yet there are also clear trends in behaviour as you move down a group.

## Mark scheme (5 marks)

1. Elements in the same group have the same number of electrons in their outer shell (same number of valence electrons)
2. The number of outer shell electrons determines how an element reacts / forms bonds, so elements in the same group react in a similar way
3. As you go down Group 1, atoms have more electron shells / the outer electron is in a shell further from the nucleus
4. There is more shielding of the outer electron from the nuclear charge by inner electron shells
5. The outer electron is lost more easily, so the element becomes more reactive / more metallic going down Group 1

## Key terms

- [group](https://www.gradenine.co.uk/glossary/group)
- [metallic character](https://www.gradenine.co.uk/glossary/metallic-character)

## 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-the-same-7093400c) · Published by Druglandscape Ltd.