In 1803, the scientist John Dalton described atoms as solid, indivisible spheres. In 1897, J.J. Thomson discovered the electron and proposed the 'plum pudding' model of the atom. Give two differences between Dalton's model of the atom and Thomson's 'plum pudding' model.
87 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.