Expanded Octed

[Payton Schwesinger 1J]

When you are drawing a Lewis structure, how do you know if you are going to be dealing with an expanded octet or not? I'm afraid I'm going to give a compound an expanded octet because if fits the number of electrons that should be present but end up with the wrong configuration.

[Nishma Chakraborty 1J]

Hi!

First, the central atom of a Lewis structure can have an expanded octet if it is capable of having a d-orbital or greater (so it has to be in the third energy level or higher/third period or below on the periodic table.) Non-metals (groups 13-17 on the periodic table) are the ones that tend to have expanded octets because they accept, rather than give away, electrons.

Hope this helps! :)

[Jingyi Li 2C]

The central atom can have an expanded octet if it is in the third energy level or higher (starting from P, S, Cl). First draw the Lewis structure following the octet rule. If you can achieve a lower energy structure (formal charge closer to zero) with an expanded octet, then add bonds or electrons to the central atom.