Table titled "Atomic and Ionic Radii." The top of the table has four columns labeled 1A, 2A, 6A, and 7A, from left to right. Under each column are three elements with their atomic radius and ionic radius labeled. Column 1A: Li, Na, K Column 2A: Be, Mg, Ca Column 6A: O, S, Se Column 7A: F, Cl, Br