Octet Rule- Every element tries to acquire 8 electrons in its outermost orbit by loosing or gaining or sharing electron.
Significance – Most of the molecules are formed by following octet rule eg. N2,O2,Cl2,Br2 etc it is useful for understanding most of the organic compounds and it applies mainly to the second period elements of the periodic table.
Limitations- Although octet rule is very useful but is not universal.In some compounds, the number of electron surrounding the central atom is less than 8.In NO,NO2 octet rule is not satisfied they are odd electron molecule In PF5,SF6,IF7 these expanded octets or super octets i.e. 10,12 and 14 electrons respectively after sharing.
