# Copper has two naturally occurring isotopes: copper-63 and copper-65. Explain what is meant by the term isotope and describe how the subatomic particles in copper-63 and copper-65 differ from each other.

> OCR GCSE Chemistry A: Gateway Science (J248) — C1.2 Atomic structure · Explain · 4 marks

> Copper is a metal widely used in electrical wiring. Its atomic number is 29.

## Mark scheme (4 marks)

1. Isotopes are atoms of the same element with the same number of protons but a different number of neutrons
2. Both isotopes have 29 protons (as atomic number is 29)
3. Copper-63 has 34 neutrons and copper-65 has 36 neutrons (mass number minus atomic number)
4. Both isotopes have the same number of electrons (29), so the electron configuration / chemical properties are the same

## Key terms

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

## Related

- [Revision notes for OCR GCSE Chemistry A: Gateway Science (J248)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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