What holds the parts of an atom together?
Opposite electrical charges of the protons and electrons do the work of holding the electrons in orbit around the nucleus. Electrons closer to the nucleus are bound more tightly than the outer electrons because of their distance from the protons in the nucleus. The electrons in the outer orbits, or shells, are more loosely bound and affect an atom’s chemical properties. The nucleus is held together by the attractive strong nuclear force between nucleons: proton-to-proton, neutron-neutron, and proton-neutron. It is extremely powerful, but extends only a very short distance, about the diameter of a proton or neutron. There are also electromagnetic forces, which tend to shove the positively-charged protons (and as a result the entire nucleus) apart. In contrast to the strong nuclear force, the electric field of a proton falls off slowly over distance extending way beyond the nucleus, binding electrons to it. The balance between the strong nuclear force pulling the nucleus together and the
