Nucleus

1. Atomic number. Mass number. Isotopes. Specific charge.

2. Internal structure of atoms. Rutherford's gold foil experiment. The discovery of nucleus

3. Closest approach.

4. Size of nuclei. Compressibility.

5. Strong nuclear force. Proposed after the discovery of neutron.

Rutherford's gold foil experiment and the discovery of the nucleus - PHET 

Isotopes - PHET     

Periodic table - ptable