Why the first tables used atomic weight
Why the first tables used atomic weight
Before protons and electrons were discovered, scientists could not use atomic number to identify the position of an element. They therefore arranged elements mainly by atomic weight, a historical term related to the relative atomic mass of an element.
Step-by-step lessons covering AQA GCSE Chemistry 1.2.2 Development of the periodic table for Foundation and Higher tier. Each lesson works through exam-style questions in Paper 1 and Paper 2 format. Nail the core quantitative topics — moles, balancing equations and calculations — early on, since they underpin higher-tier questions across every paper and topic.