Draw the Lewis structure for this element

Question

Draw the Lewis structure for SO^-2 3, including lone pairs

Answer 1

I think you probably meant to ask about SO₃^2-. It's difficult to draw Lewis structures on this platform, but I'll do my best to describe the Lewis structure and to answer to question.

Central atom = S

Valence electrons:

6 from S; 6 from each O x 3 = 18; 2 from the charge on the ion =2. TOTAL = 26 valence electrons

You would end up with S in the center with 3 O atoms bonded to it. The S would have 1 lone pair, and each O would have 3 lone pairs. This would satisfy the octet rule for ALL 4 atoms. HOWEVER, the formal charges would be +1 on S and -1 on all three O atoms.

If we move one lone pair from one of the O atoms to form a double bond with the S, we then have a structure with S in the center with 1 lone pair and 1 O double bonded to the S and this O now has 2 lone pairs. The other 2 O atoms still have 3 lone pairs. This resonance structure now has formal charges of zero on the S, zero on the O that is double bonded, and -2 on the other 2 O atoms. This is a preferred structure because it has a smaller separation of charge. Note that in this resonance structure, S has 10 electrons and violates the octet rule, but also recall that S is one of the 3p elements that can accommodate that violation. So, this would be the preferred resonance structure along with the other 2 resonance structures where you simply move the double bond from one O to the other to the other. Thus, you have 3 acceptable resonance structures.