Atoms were first to be thought of to be tiny indivisible spheres
2. The electron was discovered first, leading to the plum pudding model by JJThomson
3. The results of the alpha particle scattering experiment by Rutherford led to the conclusion that the mass of an atom was concentrated at the centre. This lead to the discovery of the nucleus. The plum pudding model was replaced with the nuclear model
4. Niels Bohr adapted the nuclear model by suggesting that electrons orbit the nucleus at specificdistances
5. Later experiments lead to the proton being discovered
6. The experimental work of JamesChadwick lead to the discovery of neutrons within the nucleus
