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Kinetic theory models the arrangement and movement of particles in solids, liquids and gases. It explains properties of substances in these different states, and what happens during changes of state.

Atoms consist of a nucleus containing protons and neutrons, surrounded by electrons in shells. The numbers of particles in an atom can be calculated from its atomic number and mass number.

Understanding how to approach exam questions helps to boost exam performance. Question types will include multiple choice, structured, mathematical and practical questions.