# Elements in the periodic table are organised into groups and periods. Explain what is meant by the terms 'group' and 'period', and describe how knowing an element's position in the periodic table can be used to predict its properties.

> WJEC A-Level Chemistry (Wales) — 2.1 Periodic table · Explain · 5 marks

## Mark scheme (5 marks)

1. A group is a column of the periodic table
2. Elements in the same group have similar chemical properties
3. A period is a row of the periodic table
4. Elements in the same period have the same number of electron shells
5. Because elements in the same group have similar chemical properties, the group an element is in can be used to predict how it will react / what reactions it undergoes

## Key terms

- [group](https://www.gradenine.co.uk/glossary/group)
- [period](https://www.gradenine.co.uk/glossary/period)
- [periodic table](https://www.gradenine.co.uk/glossary/periodic-table)

## Related

- [Revision notes for WJEC A-Level Chemistry (Wales)](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/elements-in-the-periodic-table-are-e1ad57bf) · Published by Druglandscape Ltd.