# Boron has two naturally occurring isotopes: boron-10 and boron-11. The relative atomic mass of boron is 10.8. Explain what is meant by the term 'relative atomic mass' and use the value of 10.8 to explain what this tells us about the relative abundance of the two isotopes of boron.

> WJEC GCSE Chemistry (Wales) — 2.4 Chemical analysis · Explain · 4 marks

## Mark scheme (4 marks)

1. Relative atomic mass is an average mass of an atom of an element
2. Compared to 1/12th the mass of a carbon-12 atom
3. The value takes into account the abundance of each isotope
4. Because 10.8 is closer to 11 than to 10, boron-11 is the more abundant isotope

## Key terms

- [relative atomic mass](https://www.gradenine.co.uk/glossary/relative-atomic-mass)
- [isotope](https://www.gradenine.co.uk/glossary/isotope)
- [abundance](https://www.gradenine.co.uk/glossary/abundance)

## Related

- [Revision notes for WJEC GCSE 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/boron-has-two-naturally-occurring-isotopes-bb98d3d5) · Published by Druglandscape Ltd.