This question is about historic models of the atom. 
Name the models of the atom shown in the figure above.
Compare Model Y with Model X. Refer to the structure, charge distribution, and location of mass in both models.
In 1932, James Chadwick discovered a new subatomic particle. Name this subatomic particle.
Explain how the discovery of this particle helped scientists understand isotopes.
Practise AQA GCSE Chemistry A simple model of the atom, symbols, relative atomic mass, electronic charge and isotopes with exam-style questions for Foundation and Higher tier. 64 questions covering Atoms, elements and compounds, Mixtures, The development of the model of the atom (common content with physics), Relative electrical charges of subatomic particles, Size and mass of atoms, Relative atomic mass, and Electronic structure, matched to the AQA GCSE Chemistry (8462) specification and written in Paper 1 and Paper 2 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.