The halogens The noble gases The alkali metals

The ionic radius is much larger.
They are about the same.
The atomic radius is larger.

K⁺, Ca⁺², Ar
Al, Mg²⁺, Si
Ar, Ne, Kr

Rb⁺, Sr⁺², Xe
Al⁺³, Na⁺, Ne
Br^-, Na⁺, Se^-2

Na⁺ < K⁺ < Rb⁺
Rb⁺ < K⁺ < Na⁺
Na⁺ < Rb⁺ < K⁺

Cl^- < Li⁺ < Be⁺²
Be⁺² < Cl^- < Li⁺
Be⁺² < Li⁺ < Cl^-

K⁺ < S^-2 < Cl^- < Ar
K⁺ < Ar < Cl^- < S^-2
S^-2 < Cl^- < Ar < K⁺

K < Li < Rb < Cs
Li < K < Rb < Cs
Cs < Rb < K < Li

F < Cl < Br < I
I < Br < Cl < F
F < Br < Cl < I

F < Br < Na
Na < Br < F
Br < F < Na

Al < Cs < Na
Cs < Na < Al
Al < Na < Cs