Question

Define octet rule and mention its limitation

Answer 1

Answer:

The octet rule explain the formation of the chemical bonds depending upon the nature of the element.

(Limitations of the octet rule) Incomplete octet of the central atom in some compound : the Number of electrons surrounding the central atom is less then eight .

Answer 2

Answer:

Octet rule fails to explain the following:

(1) The stability of incomplete octet molecules, i.e., the molecules with the central atom containing less than eight electrons.

For example, $\sf{BeCl_2}, {BF_3}$.

(2) The stability of expanded octet molecules, i.e., the molecules with the central atom containing more than eight electrons.

For example, $\sf{PC_5}, {SF_6}$.

(3) Observed shape and geometry of the molecules.

(4) Difference in energies and reactivities of different molecules.