Atomic and Ionic Radii

As with every group of the periodic table, moving down Group 16 adds successive electron shells, so both the atomic radius and the ionic radius ($E^{2-}$) increase steadily from oxygen to polonium (see Table 7.6). Oxygen stands out as an exception to the smooth pattern followed by its heavier neighbours: its atomic size is exceptionally small, even by the standard of a second-period element, which — as seen elsewhere in this chapter's discussion of the p …