# Explain what is meant by the term 'isotopes' and describe how the structure of two isotopes of the same element differs.

> Eduqas A-Level Physics — 1.7 Particles and nuclear structure · Explain · 5 marks

> Carbon exists in several forms. Carbon-12 and carbon-14 are two examples.

## Mark scheme (5 marks)

1. Isotopes are atoms of the same element
2. Isotopes have the same number of protons (or same atomic/proton number)
3. Isotopes have different numbers of neutrons
4. Carbon-12 has 6 neutrons and carbon-14 has 8 neutrons (correct values for both)
5. Both isotopes have the same number of electrons (6 electrons) / same chemical properties

## Key terms

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

## Related

- [Revision notes for Eduqas A-Level Physics](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)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/explain-what-is-meant-by-the-c7c0e137) · Published by Druglandscape Ltd.