Nucleus contains nucleons viz; protons and neutrons. Nucleus is not just pile of balls (neutrons and protons) as is generally depicted in many cases. And we don't know much about nucleus. Obviously linear variation of size with atomic mass number is experimented fact. What are theoretical explanations for this?
I mean nucleus density is not uniform, there is possibility of probability shells for nucleons, I don't think the nucleons just stacked up like balls. My question is not why is this variation; but why this linear variation?