SO2

Several times when doing a dot and cross diagram I have done it differently to the actual answer, ever though I swear mine makes more sense.
Using the octet rule, even though I know there is the expansion of the octet, it wants to have a full shell (even though I realise 8 electrons is not a full shel for the sulfur) and be stable etc.
So I put in a dative covalent bond between on oxygen atom; and then a double covalent bond between the other oxygen atom and the sulfur atom.
This means all the atoms have stable shells, so why does it instead form two double covalent bonds? Is 8 not a very stable number when it is to do with the third shell? Does the oxygen form a double covalent bond because less energy is required to do that than the sulfur to form a dative covalent bond?

Also, the final shape of this is non-linear and 120 degrees. In this case then does the lone pair have the same repulsion power of the two covalent bonds?
All this came up for me in the question 3 c) on page 59.