Electronic Configuration and Oxidation State

Every p-block element shares the general outer electronic configuration ns² np¹⁻⁶: all elements of a given group have an identical outer-shell configuration and differ from each other only in the principal quantum number, n. Group 18, the inert (noble) gases, has a completely filled p subshell (ns²np⁶), which is why its members are the most stable and least reactive elements of the block.

Because the block spans six groups, p-block elements show a wide range of oxidation states. The highest oxidation state (group oxidation state) an element can show equals the total number of valence electrons it carries -- so it climbs steadily from +3 in group 13 to +8 in group 18 (Table 2.1). Unlike the s-block metals, which show only positive oxidation states, several p-block elements can also show negative oxidation states: the halogens (group 17) have a strong pull toward gaining one electron to reach a stable, filled configuration, so -1 is their most commonly seen state, and the same tendency toward a negative state also appears, to varying degrees, in the pnictogen (group 15) and chalcogen (group 16) families. Table 2.1 also gi …