Groups and outer electrons
Groups and outer electrons

A group is a vertical column in the periodic table. Elements in the same main group have the same number of electrons in their outer shell, so they tend to have similar chemical properties.
Step-by-step lessons on Edexcel GCSE Chemistry 7.1 Group 1, covering 7.1.1 Classifying elements by group in the periodic table and 7.1.2 Properties and reactions of the alkali metals. 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.