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Cation - GCSE Chemistry Definition

Reviewed by: Philippa Platt

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A cation is a positively charged ion that forms when an atom loses one or more electrons. In GCSE Chemistry, understanding cations is crucial because they play a vital role in various chemical reactions and bonding.

When an atom loses electrons, it has more protons than electrons, resulting in a positive charge. Cations are often metal atoms that have lost electrons. For example, magnesium (Mg) loses two electrons to become a magnesium ion (Mg2+).

They can be found in compounds like sodium chloride, where the sodium atom becomes a cation. Recognising cations helps in predicting the outcome of reactions and understanding the properties of ionic compounds.

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Philippa Platt

Reviewer: Philippa Platt

Expertise: Chemistry Content Creator

Philippa has worked as a GCSE and A level chemistry teacher and tutor for over thirteen years. She studied chemistry and sport science at Loughborough University graduating in 2007 having also completed her PGCE in science. Throughout her time as a teacher she was incharge of a boarding house for five years and coached many teams in a variety of sports. When not producing resources with the chemistry team, Philippa enjoys being active outside with her young family and is a very keen gardener

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