The three states
The three states

Matter can exist as a solid, liquid or gas. The particle model explains each state using the particles' arrangement, separation, movement and energy.
Step-by-step lessons on AQA GCSE Chemistry 2.2.1 The three states of matter. Each one builds up to exam-style questions. Nail the core quantitative topics — moles, balancing equations and calculations — early on, since they underpin higher-tier questions across every paper and topic.