Why nuclear charge remains same when cation is smaller than parent atom?

because the addition of 1 or more electrons would result in increased repulsion among the electrons and a decrease in the effective nuclear charge. Anions are always larger than their parent atoms.This is opposite in case of anionsthis is because they have lesser electrons, while their nuclear charge remains the same. The remaining electrons are, therefore held more tightly by the protons in the nucleus and thus their radii.are smaller than the parent atoms. Dear UrvashiCations are always smaller than their parent atoms 

On removal of an electron from atom, there is no change in no of protons so there is no change in nuclear charge. Although cation has more effective nuclear charge than parent atom