Inorganic Chemistry - P Block Elements

SUMMARYp-Block of the periodic table is unique in terms of having all types of elements - metals, non-metals and metalloids. There are six groups of p-block elements in the periodic table numbering from 13 to 18. Their valence shell electronic configuration is ns2 np1-6 (except for He).

Differences in the inner core of their electronic configuration greatly influence their physical and chemical properties. As a consequence of this, a lot of variation in properties among these elements is observed. In addition to the group oxidation state, these elements show other oxidation states differing from the total number of valence electrons by unit of two.

While the group oxidation state is the most stable for the lighter elements of the group, lower oxidation states become progressively more stable for the heavier elements. The combined effect of size and availability of d orbitals considerably influences the ability of these elements to form π-bonds. While the lighter elements form pπ-pπ bonds, the heavier ones form dπ-pπ or dπ-dπ bonds.

Absence of d orbital in second period elements limits their maximum covalence to 4 while heavier ones can exceed this limit. Boron is a typical non-metal and the other members are metals. The availability of 3 valence electrons (2s 2 2p1 ) for covalent bond formation using four orbitals (2s, 2px, 2py and 2pz ) leads to the so called electron deficiency in boron compounds.