Answer:
The ionic radius is the the distance from the nucleus to the outermost electrons in a ion. While the atomic radius is the distance from the nucleus to the normal valence electrons.The ionic radius is half the distance between two gas atoms that are just touching each other. If the atom loses its outermost electron (positively charged or cation), the ionic radius is smaller than the atomic radius because the atom loses an electron energy shell.
Step-by-step explanation: