Octet Exceptions

[Caroline C 1G]

Do you automatically add any extra electrons to the atoms that are exceptions to the octet rule? For example, when oxygen and sulfur bond to form sulfur dioxide, 18 electrons are involved. However, when you draw the bonds, only 16 electrons are used. In lecture, we added the two extra electrons to sulfur. Does this apply to all Lewis Structures involving elements that don't adhere to the octet rule?

[MichelleT_1L]

Yes, the elements P, S, Cl, and any element that is energy level 3 or higher and has access to the d-orbital will not adhere to the octet rule, and thus will be able to hold additional electrons when needed in making Lewis Structures.

[Tatiana R Dis 3E]

Will the extra electrons always be added to the central tom? What if there are two central atoms?

[Ya Gao]

I think it depends on what the central atoms are. Like we said before, if the central atom is P, S, or Cl, they can have extra electrons around them because they do have a d orbital. And if there are two central atoms, they still have have more electrons depending on what they are. Hope it makes sense.

[Salman Azfar 1K]

I think with regards to where the electrons are added, usually only one or two of the atoms in the structure (if I had to guess) will actually be able to handle an expanded octet. We have not really covered any extremely complex structures, though if you are personally interested in the topic Dr. Lavelle would probably explain it in his office hours. For the most part, all the structures we have looked either follow the octet rule normally or only have one atom with an exception.