Can anyone explain why the electron cannot be a constituent of the nucleus using the uncertainty principle?
It follows from the uncertainty principle that if an electron were confined to a volume of nuclear size, it would have to have a whole lot of variance in momentum. That fact alone doesn’t prove that it couldn’t be part of the nucleus, but it would take a force much stronger than electrostatic attraction to keep it in there. This was realized early on when folks originally proposed that a nucleus like helium consisted of 4 protons and 2 electrons. The problem was resolved when the neutron was discovered.
