[smghz]

So, for SO3, the common answer for the resonance structures number is three. A professor online said seven.



But I kinda have to argue that maybe it's even more than seven.

I mean, S has expanded valence shell as a period 3 element. So, in addition to the four bonds it can make (with s and p subshell electrons), it can use 5 more bonds composing the d subshell for a total of 9 bonds, and still be fine. It may not be the most stable, nor have the least formal charge, but it still works.

So, why don't people list like ten or fifteen resonance structures aside from those three with only sufficient (not expanded) octets??? I literally saw some people use expanded valence shells to draw resonance while others don't!!!