1 . p-Block elements : Elements belonging to groups 13 to 18 of the periodic table are called p-block elements .
2 . General electronic configuration of p-block elements : The p- block elements are characterized by the ns 2 np 1-6 valence shell
electronic configuration .
3 . Representative elements : Elements belonging to the s and p- blocks in the periodic table are called the representative elements or main group elements .
4 . Inert pair effect : The tendency of ns 2 electron pair to participate in bond formation decreases with the increase in atomic size . Within a group the higher oxidation state becomes less stable with respect to the lower oxidation state as the atomic number increases . This trend is called ‘ inert pair effect ’. In other words , the energy required to unpair the electrons is more than energy released in the formation of two additional bonds .
5 . Nitrogen family : The elements of group 15 – nitrogen ( N ), phosphorus ( P ), arsenic ( As ), antimony ( Sb ) and bismuth ( Bi ) belong to configuration is ns 2 np 3 .
6 . Oxygen family : Group 16 of periodic table consists of five elements – oxygen ( O ), sulphur ( S ), selenium ( Se ), tellurium ( Te ) and polonium ( Po ). Their general electronic configuration is ns 2 np 4 .
7 . The halogen family : Group 17 elements , fluorine ( F ), chlorine ( Cl ), bromine ( Br ), iodine ( I ) and astatine ( At ), belong to halogen family . Their general electronic configuration is ns 2 np 5 .
8 . Group 18 elements : Helium ( He ), neon ( Ne ), argon ( Ar ), krypton ( Kr ), xenon ( Xe ), and radon ( Rn ) are Group 18 elements . They are also called noble gases . Their general electronic configuration is ns 2 np 6 except helium which has electronic configuration 1s 2 . They are called noble gases because they show very low chemical reactivity .