The model of the atom has changed when scientists found evidence that the existing model could not explain.
Which row correctly links a piece of evidence to the change it caused in the model?
Evidence: most alpha particles passed straight through gold foil. Change: the nucleus is positively charged.
Evidence: electrons were discovered inside atoms. Change: atoms have a small, dense nucleus at the centre.
Evidence: atoms have more mass than their protons alone. Change: electrons move in fixed shells.
Evidence: a few alpha particles bounced back from gold foil. Change: positive charge is in a tiny nucleus.
51 exam-style questions on OCR GCSE Chemistry 1.2 Atomic structure, covering 1.2.1 Development of the atomic model, 1.2.2 The nuclear model and the size of atoms, and 1.2.3 Subatomic particles in atoms and ions. Each one has a worked solution and a mark scheme showing where the marks go.