hybrid structure

[josmit_1D]

are resonance hybrid structures usually just for carbon- hydrogen bonds?

[EvanWang]

No, resonance happens when you have the same arrangement of atoms, but different arrangements of electrons. For example, in ClO- the single bond could be in four different locations.

[Victor James 4I]

its not specific to those atoms

[andrewcj 2C]

Be wary of resonance structures any time you see a multiple bond, as you just have to think about if you could put the multiple bond somewhere else.

[Manav Govil 1B]

Hybrid structures are just resonance structures interpreted through one diagram. The double bonds are represented as one solid and one dotted, and there are enough electrons on each atom considering a double bond is present. Any bond can have resonance.