Is a positive ion larger or smaller than its parent atom?

Answer by  chemteach (100)

A positive ion or cation is smaller than the atom it can from. This reduction in size is the result of the loss of valence electrons and reducing the diameter of an atom by an energy level. For example, Ca+2 with 3 energy levels is smaller than Ca, with an electron configuration ending on the 4th energy level.

Answer by  Mac44 (479)

This can be a complicated question due to complicated physics and chemistry at the nuclear level, but in most cases, the ion is smaller because it is missing electrons.