# Electron

A tiny particle with a negative charge that moves around the nucleus. Its mass is almost nothing compared with a proton.

Chemistry (school) · Part 01: Atoms and matter · Card 7 of 10 · Last updated 2026-10-19

## Analogy

Electrons are like planets circling a sun, though they move in a fuzzier way.

## In practice

A neutral atom has equal numbers of electrons and protons, so the charges cancel.

## Practice

### Flashcards

- **Which particle has almost no mass?** The electron.
- **Why is a neutral atom neutral?** It has the same number of positive protons and negative electrons.

## Questions people ask

### Why are electrons important in chemistry?

Electrons on the outside of an atom take part in reactions. They are shared, given away or taken to form bonds. The number of outer electrons decides how an element reacts and which bonds it makes. The nucleus stays unchanged in chemical reactions.

### Do electrons really orbit like planets?

The planet picture is a useful simple model for school. In reality electrons behave more like a fuzzy cloud, and we can only say where they are likely to be. For GCSE-level work, the shell model of electrons in fixed energy levels is all you need.

## Related concepts

- [Proton](https://studyvisually.com/learn/science/chemistry-school/chemistry-school-part-1/chemistry-school-part-1-concept-5)
- [Atom](https://studyvisually.com/learn/science/chemistry-school/chemistry-school-part-1/chemistry-school-part-1-concept-1)
- [Neutron](https://studyvisually.com/learn/science/chemistry-school/chemistry-school-part-1/chemistry-school-part-1-concept-6)

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