So when we talk about cations, or when neutral atoms become can ions, there is a loss of electron, and this shrinks the element to a smaller size. Now, on the contrary, let's look at anions. So what happens to anion? Suppose now we have a neutral atom with a plus one charge and a minus one charge, forming a neutral charge. And now suppose it gains an electron from some other atom, probably metal. Now what will happen is it will gain a new outer shell, forming this outer shell and forming this empty space in between.