Atomic number fixes identity
Atomic number fixes identity
The atomic number is the number of protons in the nucleus. Every atom of one element has the same proton number, and no two elements have the same proton number.
Step-by-step lessons on Edexcel GCSE Chemistry 2.2.2 Periods, groups, metals and non-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.