# An atom of element X has an atomic number of 11 and a mass number of 23. State the number of protons, neutrons, and electrons in a neutral atom of element X, and name the element.

> Pearson Edexcel International GCSE Chemistry (4CH1) — 1.2 Atoms · State · 4 marks

## Mark scheme (4 marks)

1. 11 protons
2. 12 neutrons (mass number − atomic number = 23 − 11)
3. 11 electrons (equal to the number of protons in a neutral atom)
4. Sodium (Na)

## Key terms

- [atomic number](https://www.gradenine.co.uk/glossary/atomic-number)
- [mass number](https://www.gradenine.co.uk/glossary/mass-number)
- [electron](https://www.gradenine.co.uk/glossary/electron)
- [atom](https://www.gradenine.co.uk/glossary/atom)

## Related

- [Revision notes for Pearson Edexcel International GCSE Chemistry (4CH1)](https://www.gradenine.co.uk/learn)
- [How to answer "State" 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/an-atom-of-element-x-has-730bd029) · Published by Druglandscape Ltd.