Significance of octet rule:
       The octet rule successfully explains the formation of chemical bonds depending upon the nature of the element.
     It is used to determine stability in atoms.
     The octet rule helps to figure out how atoms will bond with one another.  

limitations of octet rule are:
 Some limitations of the octet rule are: It cannot be applied to the nonmetals after silicon in the periodic table. These elements can “expand their octet” and have more than eight valence electrons around the central atom. Examples are PF₅ , SF₆ and H2SO4 . Helpful 1 Confusing 1 Molecules with an odd number of electrons such as NO and NO₂ cannot satisfy the octet rule. At least one atom must have an odd number of electrons. In some molecules the central atom cannot possibly have eight valence electrons. For example, LiCl, BeCl₂ and BCl₃ do not obey the octet rule.