Question

Are there 2 pi bonds in SO2 or is there one alternating pi bond during resonance?

Answer 1

I think it would be more appropriate to say one alternating bond during resonance since sulfur can only form three bonds at once. This would give sulfur a formal charge of +1 and the single-bonded oxygen a formal charge of -1.

Answer 2

So would SO2 have 2 sigma bonds and 1 alternating pi bond?

Answer 3

Yes