Ga (галлий).  Ge (германий).  As (мышьяк).
7.35 Consider S, Cl, and K and their most common ions. (a) List the atoms in order of increasing size. ATOM RADIUS Cl < S < K S is on left of Cl in same period, so is larger. K has four shells, S only has three. (b) List the ions in order of increasing size. ION RADIUS K+ < Cl-< S2-