The Structure of the Atom (AQA GCSE Chemistry): Revision Notes
📚 Revision Notes
1.1.7 The Structure of the Atom
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Atoms: Each atom has negatively charged electrons orbiting a positively charged nucleus.
- Atoms contain a nucleus and orbits (shells).
The Nucleus:
- Contains protons and neutrons.
- P****rotons are p****ositively (+) charged.
- Neut****rons are neut****rally (0) charged (no charge).
- Therefore, the nucleus has an overall positive charge.
The Orbits (Shells):
- Contain electrons.
- Electrons are negatively (-) charged.
- Electrons move around the nucleus in their orbits (shells).
- Although electrons are tiny, they cover a large area in their orbits.
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Atoms have no overall charge because the number of electrons equals the number of protons.
| PARTICLE | LOCATION | RELATIVE MASS | CHARGE |
|---|---|---|---|
| Proton | Nucleus | 1 | +1 |
| Neutron | Nucleus | 1 | 0 |
| Electron | Orbit | 0.0005 | -1 |
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If an atom gains or loses an electron it becomes an ion. Gaining an electron —> Negative ion Losing an electron —> Positive ion