why cause ionic radii to be smaller or larger?

Question

hello. Im confused. Why is it the ionic radii larger in anion? or smaller in cation? what are the reasons to this? i try to find the answer on some websites, but im not so satisfied with them. Thanks

Answer 1

The cations tend to give the electrons in the outer shell in order to empty that outer shell.
After emptying the outer shell, the cations have the same outer shell that the noble gaz of former period which is smaller .

The anions tend to fill their outer shell and so to increase their radii since electrons tends to repel each other and so increase the dimensions of the ions

Answer 2

Smaller in a cation as once an atom loses and electron, there is less repulsion between the other electrons, therefore they get attracted more by the nucleus. Anions are larger as once they have gained an electron, the extra repulsion causes the atimic radii to increase.