What is phosphate's electron configuration?

The charges formally reside on the oxygen atoms, as we would expect for this strongly electronegative atom.

There are ##5+4xx6+3=32" valence electrons"## for ##PO_4^(3-)##, and a formal Lewis structure of ##O=P(-O^-)_3## is proposed. What is your prediction with respect to the structure of the phosphate ion?

Note that when we titrate phosphporic acid ##H_3PO_4## with sodium hydroxide, we get mainly ##HPO_4^(2-)## at the endpoint in aqueous solution.