Positive Ions (AQA GCSE Physics Combined Science): Revision Notes
📚 Revision Notes
4.1.5 Positive Ions
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Atoms are generally neutral, with the same number of protons in the nucleus as electrons orbiting around it.
However, atoms can lose or gain electrons due to various interactions, forming charged particles known as ions:
- If an atom loses one or more electrons, it becomes a positively charged ion.
- If an atom gains one or more electrons, it becomes a negatively charged ion.
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For example, a helium atom has two electrons orbiting its nucleus.
The atom is neutral as it has two positive protons and two negative electrons.
A helium atom that has lost or gained an electron is an ion.
If the ion has two positive protons but one negative electron, it is a positive ion.
If the ion has two positive protons but three negative electrons, it is a negative ion.