Colours and states at room temperature
Colours and states at room temperature
A halogen is an element in Group 7 with seven electrons in its outer shell. Halogens exist as diatomic molecules, including Cl2\text{Cl}_2Cl2, Br2\text{Br}_2Br2 and I2\text{I}_2I2.
Step-by-step lessons on Edexcel GCSE Chemistry 7.2.1 Physical properties of the halogens. 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.