1. Sulfur dioxide, or SO2 , has two resonance structures which contribute equally to the overall hybrid structure of the molecule. However, a third Lewis structure can be drawn for SO2 which is more stable in theory, but doesn't quite match experimental data.
2.
[tex] \color{red} = \frac{No. \: of \: bonding \: electron \: pairs}{No. \: of \: bonded \: atoms} [/tex]
[tex]In \: each \: resonance \: contributor, \\ there \: are \: six \: bonding \: electron \\ pairs \: and \: four \: atoms \: bonded \\ to \: the \: SS \: atom. \: Thus,[/tex]
[tex]BO = \frac{6}{4} = 1.5
[/tex]