Do atoms not break apart into protons and neutrons because the forces between nucleons are stronger than other forces?

Answer 1

Nuclei of atoms do not break apart into protons and neutrons because the strong atomic force between the nucleons is greater than the electromagnetic force that would tend to push protons apart, by about a factor of 100. Also, the electromagnetic force is stronger by many orders of magnitude than the weak atomic force (1013) and gravity (1039), so this puts the strong atomic force at the top of the chain, so to speak.

Strictly speaking, the strong atomic force is what holds quarks and other particles together to form protons and neutrons. What holds protons and neutrons together is actually the residual strong force, or what we call the nuclear force. It is weaker than the strong atomic force, but still stronger than electromagnetism. Unlike the strong atomic force, however, its effects diminish with distance, more so than the competing electromagnetic force, which is why larger nuclei, with atomic numbers greater than 82, tend to be unstable.