## Chemistry and Chemical Reactivity (9th Edition)

Radius increases from right to left and top down in the periodic table, so a) $F(G17, P2)\lt O(G16, P2)\lt S(G16, P3)$ Ionization energy increases from left to right and bottom up in the periodic table, so b) S, S and Se are in group 16 vs 15 for P and 14 for Si, but S is in the third period, vs fourth for Se. d) $Cs(G1, P6)\lt Ba(G2, P6)\lt Sr(G2, P5)$ Radius is bigger in more negatively charged ions, so c) $N^{3-}$