What is the oxidation number of the element n in the compound n2o5? 1. 3 2. 6 3. 5 4. 2 5. - 6 6. 4 7. - 2 8. - 3 9. - 5 10. - 4?

Answer is: oxidation number of nitrogen is + 5 (3. 5).

Oxygen has greater electronegativity than nitrogen, so oxygen has negative oxidation number, in this compound - 2, so oxidation number of nitrogen is + 5:

2 · x + 5 · (-2) = 0.

2x = 10.

x = 10 : 2.

x = 5; oxidation number of nitrogen.

The sum of the oxidation numbers in a neutral compound is zero.