What are the limitations of the octet rule?
The octet rule states that atoms can combine either by transferring or by sharing their valence electrons to attain an octet of electrons in their valence shell.
One limitation of the octet rule is that 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.
And so does the
Molecules with an odd number of electrons such as
One atom must have an odd number of electrons.
In some molecules the central atom cannot possibly have eight valence electrons. For example,