Answer
Please see the work below.
Work Step by Step
(a) We know that if the electron in this system is replaced by a proton, then mutual repulsion takes place and the protons move away to infinite separation. Thus, the protons gain kinetic energy and there is a corresponding decrease in the positive electric potential energy. As a result, the electric potential energy of the system increases by replacing the electron with a proton.
(b) We know that if the hydrogen atom is replaced by an electron, repulsion takes place between the two electrons and they move off to infinity. Thus, the tow particles in a system that are approaching infinity must be approaching zero potential energy. Consequently, the potential energy of the system increases when the proton is replaced with an electron.
