as the electron gets fatter and less dense less cojupled with its proton it takes less to move it away from its spot and make it bigger. eventually it is so big and less dense that it might couple with another atom
in the neclus the protons want to go towards the electrons of other neutrons so they are attracted thus, but when they get close the proton associated with that electron pushes them away. this is why there can never be an absolute zero atom. and this is what binds the necleus and keeps it from collapsig.