Resonance and Electrons [ENDORSED]

[Jana_Lang_2B]

So in lecture, Lavelle mentioned that electrons involved in resonance structures are delocalized. What exactly does localized/delocalized electrons mean?

[Omer Lavian 2K]

Let's use the example of benzene. As you can see on page 81 of the course reader, there are two different possible Lewis structures for benzene. In this case, this simply means that the double bonds and single bonds in the ring can be rearranged, resulting in two different possible Lewis structures. In reality, benzene rings are not bound by alternating double and single bonds. Instead, each C-C bond in the benzene ring is of the same length and strength, a length and strength of bond between a single bond and a double bond. This averaging of the single and double bonds is called resonance. As a result, the six "inner" electrons, meaning the six electrons not being directly shared by a pair of carbon atoms (If you look at the Lewis structures, these are the lines INSIDE the ring.), are not bound, or LOCALIZED, to any particular bond. Rather, these "inner" electrons are DELOCALIZED, meaning that they are spread throughout the molecule. Hope this was helpful!