Key Stage 4
Meaning
An Ion is a particle that has a different number of protons to electrons.
About Ions
- An atom contains the same number of protons as electrons. When an atom loses or gains electrons it becomes an ion.
- Ions can be positively charged or negatively charged.
- If an atom gains electrons it becomes a negatively charged ion since there are more electrons than protons and electrons carry a negative charge.
- If an atom loses electrons it becomes a positively charged ion since there are more protons than electrons and protons carry a positive charge.
| Atom | Ion |
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| A Lithium atom has 3 protons and 3 electrons so it is neutral. | A Lithium ion has 3 protons and 2 electrons so it has a positive charge. |
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| A Fluorine atom has 9 protons and 9 electrons so it is neutral. | A Fluorine atom has 9 protons and 10 electrons so it is negative charge. |