Answer
See explanation
Work Step by Step
$\textbf{The more favorable}$ $\textbf{(negative) electron affinity:}$
(K and Cs): K (Smaller size, stronger attraction for electrons)
(Te and Br): bR (Halogens have the highest electron affinities)
(Ge and Se): Se (Nonmetals attract electrons more than metalloids)
$\textbf{The higher ionization energy:}$
(K and Cs): K (Higher up in Group 1, electrons held more tightly)
(Te and Br): Br (Smaller atom, electrons closer to nucleus)
(Ge and Se): Se (Smaller size, stronger nuclear pull)
$\textbf{The larger size (atomic radius):}$
(K and Cs): Cs (Lower period, more electron shells)
(Te and Br): Te (Lower in Group 16, more electron shells)
(Ge and Se): Ge (Left of Se in the same period, less nuclear pull)
