Which pair represents isotopes of the same element?
12 protons, 12 neutrons and 13 protons, 12 neutrons
8 protons, 8 neutrons and 9 protons, 7 neutrons
17 protons, 18 neutrons and 17 protons, 20 neutrons
6 protons, 6 neutrons and 7 protons, 5 neutrons
46 exam-style questions on Edexcel GCSE Chemistry 2.1 Atomic structure, covering 2.1.1 Development of the atomic model, 2.1.2 Structure of the atom and subatomic particles, 2.1.3 Mass number, isotopes and relative atomic mass, and 2.1.4 Calculating relative atomic mass from isotopic abundance. Each one has a worked solution and a mark scheme showing where the marks go.