What is the oxidation number of chromium in K2CrO4?

Explanation

K₂CrO₄ (O.N of K) X 2 + O.N of Cr + (O.N of oxygen) X 4 = 0
1 X 2 + X + -2 X 4 = 0
2 + x + -8 = 0
2 + x - 8 = 0
x = 8 - 2 = + 6