We had a discussion on the relative size of atoms, relative to the atomic number. We discussed why some atoms of higher atomic number and mass have smaller radii than others. We talked about how the nuclear charge will affect the force on the electron by the proton. I showed Bobby images of hydrogen and helium atoms and we compared radii due to EM force. Discuss why in quantum physics, things are not as predictable and are more chaotic than in Newtonian physics.