Question

The combination of atoms to form molecules is based on octet rule. Give two limitations of this rule.

Answer 1

(i) It cannot explain the formation of molecules like BeF₂, BF₃ in which the central atom has less than 8 electrons in its valence shell. 

(ii) It cannot explain the formation of molecules such as PF₂,SF₆ etc. in which central atom has more than eight electrons in its valence shell.