Why does the octet rule have exceptions?
1 Answer
Exceptions to the octet rule come from the presence of the orbital d
Explanation:
Elements of the third raw in the periodic table and beyond can carry more than 8 electrons on their outermost shell because of the additional room (space) on their orbital d.
Only elements of the first and second raws of the periodic table can carry a maximum of 8 electrons on their outermost shell because they only have s and p orbitals available to host electrons (with the exception of hydrogen and helium they obey the duet rule).
For example, the electronic configuration of oxygen (second raw element) O: 1
Oxygen can host 2 more electrons on its outer shell 2 and therefore 2 + 4 + 2 = 8 electrons.
However, sulfur (third raw element) S: 1
Sulfur can host up to 12 more electrons on its outer shell 3, two electrons on p and 10 electrons on d and therefore 2 + 4 + 2 + 10 = 18 electrons.
This is why oxygen has an oxidation number of -2 in general with the exception of
If we look at the Lewis structure of