[smilegirl]

Does a benzene ring have resonance structures even if it is highly substituted?
Thanks

[spirochete]

When you draw resonance structures for benzene which orbitals are the electrons delocalized into?  What type of orbitals are they?  What type of oribital would be used to make bonds to substituents? 

[smilegirl]

the orbitals are sp2, so there would be one sigma and one pi bond

[spirochete]

That's correct each carbon is SP2 hybridized, although this means it makes 3 sigma bonds with its sp2 hybrid orbitals and a Pi bond with its P orbital.  But you still need to think about which oribtals are involved in resonance to understand the answer to your question.

If you want you can also make a model of benzene to see the orientation of the orbitals.  The P orbital in each atom is perpindicular to the plane of the sigma bonding oribitals.