What is the oxidation number of chromium in Cr₂O₇^2-?

Question

Quizplus · Accepted Answer

In this compound, the oxidation number of sulfur is -2 (unless it is bonded to a more electronegative element), and the oxidation number of oxygen is -2. We can set up the equation: 
1(Cr) + 1(S) + 12(U1B) + 1(S) + 12(U1B) + 0(O) + 1(S) + 17(U1B) + 0(S) + 1(P12-) + 1(S1S1) + 1(P0-) = 0 
Simplifying this, we get: 
1(Cr) + 32(U1B) - 2 = 0 
Therefore, the oxidation number of chromium is +6.

What Is the Oxidation Number of Chromium in Cr2O72-

What Is the Oxidation Number of Chromium in Cr₂O₇^2-