# Elements in the periodic table are arranged in periods and groups. Explain what is meant by the terms 'period' and 'group', and describe how the arrangement of electrons in an atom is related to its position in the periodic table.

> Eduqas A-Level Chemistry — 2.1 Periodic table · Explain · 5 marks

## Mark scheme (5 marks)

1. A period is a row of the periodic table
2. Elements in the same period have the same number of electron shells
3. A group is a column of the periodic table
4. Elements in the same group have similar chemical properties
5. Elements in the same group have the same number of electrons in their outer shell

## Key terms

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

## Related

- [Revision notes for Eduqas A-Level Chemistry](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-089e4e57) · Published by Druglandscape Ltd.