With reference to the discovery of the structure of an atom, explain in brief - William Crookes experiment for the discovery of cathode rays, followed by - J.J. Thomsons experiment pertaining to the constituents of the cathode rays.
State which sub-atomic particle was discovered from his experiment.

Explain in brief - Goldstein's experiment which led to the discovery of the proton and - Lord Rutherford's experiment which led to the discovery of the atomic nucleus.

Draw a neat labeled diagram representing an atom. Name the three sub-atomic particles in the atom & represent them symbolically showing the mass & charge of each. State where the sub-atomic particles are present in the atom.

Define the term - 'atomic number' of an atom. If an atom 'A' has an atomic number of - eleven, state the number of protons & electrons it contains.