[MorganFreeman]

My book states that the resonance structures with a 2+ formal charge on sulfur and a - charge on the oxygens without hydrogens is the "normal structure". I don't see this one through.
Why not the structure where the formal charge on each atom is 0?

My book states that this "normal structure helps explain how H2SO4 donates a proton. Can anyone guide my understanding on this one?

[AWK]

A structure with a splitted charges is never normal. But this is a common attempt to extending an octet rule to more than 7 (Li to F)  elements

[MorganFreeman]

I still don't understand why this compound is likely to donate a proton.