What does a 3d model of the molecular structure of lead sulfate look like?

Answer

The sulphate ion is sp³ hybridized meaning it has a tetrahedral shape(triangular pyramid, base and 3 sides). The sulfur sits in the middle of this pyramid with 4 oxygens at the 4 points. In the Lewis dot structure, two of these oxygens have a single bond to the sulfur resulting in a -1 charge on each oxygen, and a -2 charge on the whole ion.
However, there is more than one way to draw the Lewis dot structure. These alternate ways are called resonance forms, and these are VERY important to understanding the structure correctly. There are about a dozen ways to draw the Lewis dot structure, all of which are correct, and each one is considered a unique resonance form! For instance, without moving the atoms on the page, there are 6 equivalent ways to draw 2 double bonds and 2 single bonds to the four oxygens! Try it! They are all equivalent. NOTE: You will often see the Lewis dot structure of sulfate as being just a single structure (with two double bonds and two single bonds). While it is correct, the molecule does not really look like that! To correctly represent bonding in the molecule, all of the many resonance forms must be considered.
Due to resonance, each oxygen is equivalent to the other 3 -- all bond lengths are identical and each oxygen has just as much electron density as the others. The ion is completely symmetrical and is perfectly tetrahedral.
The sulfate ion bonds to the lead(II) ion through an ionic bond. The lead ion sits next to the sulfate ion and they are attracted and bonded to each other through the attraction of the +2 charge on lead and the -2 charge on sulfate.
See Web Links for a picture of the sulfate ionAgain, don't be fooled by the single Lewis dot structure on this Wikipedia page. It is correct as a Lewis dot structure, but not as an accurate representation of what the bonding is really like. The "ball model" picture is more accurate!