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Metal Oxide - GCSE Chemistry Definition

Reviewed by: Richard Boole

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A metal oxide is a compound formed when a metal reacts with oxygen. It contains metal ions and oxide ions (O2-). Most metal oxides are solids at room temperature and often occur as minerals in nature.

For example, when iron reacts with oxygen, it forms iron(III) oxide (Fe2O3), commonly known as rust.

Many metal oxides act as bases and can react with acids to form a salt and water in neutralisation reactions:

metal oxide + acid → salt + water

Metal oxides have various applications, such as in building materials (e.g. cement and ceramics) and electronics (e.g. semiconductors). Understanding metal oxides is important in GCSE Chemistry for explaining oxidation, metal reactivity, and acid–base reactions.

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Richard Boole

Reviewer: Richard Boole

Expertise: Chemistry Content Creator

Richard has taught Chemistry for over 15 years as well as working as a science tutor, examiner, content creator and author. He wasn’t the greatest at exams and only discovered how to revise in his final year at university. That knowledge made him want to help students learn how to revise, challenge them to think about what they actually know and hopefully succeed; so here he is, happily, at SME.

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