What are the limitations of Octet rule.

Asked by rajeshxavierian | 19th Jan, 2019, 04:07: PM

Expert Answer:

Limitations of octet rule:

  • The incomplete octet of the central atom

            In some compounds, the number of electrons surrounding the central atom is less than eight.

            This is especially the case with elements having less than four valence electrons. Examples are LiCl, BeH2 and BCl3.

  • In a number of compounds of thir period elements, there are more than eight valence electrons around the central atom. 
            This is termed as the expanded octet. The octet rule does not apply in such cases.

            Examples of such compounds are SF6, H2SO4.

  • The rule is based on inert nature of noble gases. However, some noble gases (for example xenon and krypton) combine with oxygen
            and fluorine to form a number of compounds like XeF2, KrF2, XeOF2 etc.

Answered by Varsha | 20th Jan, 2019, 11:10: AM