I have drawn the following resonance structures for SO3-:
Those are all representations of SO3
(the neutral species).
Are you sure you want to be drawing structures for SO3-
and not SO32-
would be a radical anion, ie one unpaired electron on S (whereas SO32-
has a lone pair on S, and SO3
no lone pair on S).
These are SO3-
, you sould probably include the unpaired electron on S when you draw in in your work.
(-) O-S=O (-)
Did you mean to put a minus charge here?