H2SO4 Step 8

Picture so Far:
(numbers next to atoms are their formal charges)
Expanded octet resonance structures of H2SO4, step 8
The bottom resonance structure is the best because all the formal charges are zero.  We could go on expanding the S octet, but this would start to move the formal charges away from zero;  thus we stop here.
Total Valence Electrons 32
Used so Far  6(2)+2(4)+2(6) = 32
Remaining 0