Question

What is the oxidation number of the sulfur atom in $L{i}_{2}S{O}_4$ ?

Answer 1

Sulfur in sulfate expresses it maximum oxidation state, its Group Number, +VI.

How? Well, as you know the sum of the oxidation numbers MUST equal the charge on the ion..........

And so Soxidationnumber+4×Ooxidationnumber=−2Soxidationnumber+4×Ooxidationnumber=−2 ? what are the oxidation number of sulfur here ?