Specification Point 1.8:
Understand how to classify a substance as an element, compound or mixture


Class Definition
Element A substance made up of atoms that all contain the same number of protons (one type of atom) and cannot be split into anything simpler. There are limited types of element.

Example: Hydrogen, Oxygen, Carbon

Compound A pure substance made up of two or more elements chemically combined together. There are unlimited types of compound. Cannot be separated by physical methods of separation.

Example: Copper (ii) Sulphate, Calcium Carbonate

Mixture A combination of two or more substances (elements and/or compounds) that are not chemically joined together. Can be separated by physical methods of separation.

Example: Sand and water, oil and water


Element, compound, mixture, Edexcel IGCSE Chemistry

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Author: Jamie

Jamie got a First class degree in Chemistry from Oxford University before going on to teach chemistry full time as a professional tutor. He’s put together these handy revision notes to match the Edexcel IGCSE Chemistry specification so you can learn exactly what you need to know for your exams.