I don't know specifically what you are asking about, but, and Ion is called an ion because the original atom HAS lost electrons.
Electrons are extremely small, and have an unfathonambly small mass, 9.11 x 10 -31 kg so when an atom loses an electron, it is as though it has lost no mass at all.
Protons and neutrons on the other hand are on the order of 1.6 x 10 -27 kg which is roughly 1000x more massive than an electron. So losing a proton would result in much more "mass loss" so to speak, than losing an electron. Electrons however, are much more easily lost than protons, in fact, chemical bonding rests solely on the fact that electrons can be lost or gained, and has nothing to do with the movement of protons.