How the periodic table is organised
How the periodic table is organised
The modern periodic table arranges elements in order of increasing atomic number. Atomic number is the number of protons in the nucleus, so it identifies the element uniquely. A neutral atom has the same number of electrons as protons.
Step-by-step lessons on Edexcel GCSE Chemistry 2.2 The periodic table, covering 2.2.1 Mendeleev's periodic table, 2.2.2 Periods, groups, metals and non-metals, and 2.2.3 Electronic configuration and position in the periodic table. 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.