Question: how many valence electrons are found in the polyatomic anion sulfate so42-?
Answer: Sulfur by itself has six valence electrons, with no bonds shown. Sulfate (SO42-) is a polyatomic ion (not by itself), and has bonds because it shares e- with oxygen to complete an octet. In a Lewis Structure drawing of Sulfate, we look at the total number of valence electrons (6e- + 4x6e- + 2e-=32e-) in the ion.