# Benzene is described as an aromatic compound. Explain what is meant by the term 'aromatic' and describe the structure of benzene that makes it aromatic.

> Eduqas A-Level Chemistry — 4.2 Aromaticity · Explain · 5 marks

> Benzene has the molecular formula C₆H₆. It was originally thought to contain alternating single and double carbon–carbon bonds, but experimental evidence showed this was not the case.

## Mark scheme (5 marks)

1. Benzene has a planar (flat) ring of six carbon atoms
2. Each carbon atom contributes one electron to a delocalised system / the electrons are delocalised over the whole ring
3. All carbon–carbon bond lengths in benzene are equal / the same / intermediate between a single and double bond
4. The delocalised pi (π) electrons form a ring of electron density above and below the plane of the ring
5. This delocalisation makes benzene more stable than expected / gives extra stability (resonance stabilisation) compared to a structure with alternating double bonds

## Key terms

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

## 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)
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Source: [GradeNine](https://www.gradenine.co.uk/q/benzene-is-described-as-an-aromatic-0f971406) · Published by Druglandscape Ltd.