Calculate the oxidation number of s in S2O8^2-

Given problem:

    S₂O₈²⁻

Find the oxidation number of S;

Oxidation number presents the extent of oxidation of each atom of elements a molecular formular or formula unit or an ionic radical.

  For radicals:

          "the algebraic sum of all the oxidation numbers of all atoms in an ion containing more than one kind of atom is equal to the charge on the ion  "

 S₂O₈²⁻;   oxidation number of O is usually -2

             2(S) + 8(-2) = -2

               2S - 16  = -2

               2S = -2 + 16

                2S  = 14

                   S  = +7

The oxidation state of S in the radical is +7

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer