Chapter 7, Problem 65QP

Indicate which one of the two species in each of the following pairs is smaller: $\left(\text{a}\right){\text{ Cl or Cl}}^{\text{-}}\text{, }\left(\text{b}\right){\text{ Na or Na}}^{\text{+}}\text{, }\left(\text{c}\right){\text{ O}}^{\text{2-}}{\text{ or S}}^{\text{2-}}\text{, }\left(\text{d}\right){\text{ Mg}}^{\text{2+}}{\text{ or Al}}^{\text{3+}}\text{, }\left(\text{e}\right){\text{ Au}}^{\text{+}}{\text{ or Au}}^{\text{3+}}\text{.}$