Question

Where do you find oxidation numbers?

Answer 1

Tattooed on the backs of the atoms' necks.

Explanation:

For a given compound, you must calculate them. The sum of the oxidation numbers ALWAYS equals the charge on the ion or molecule. See here, here, and here for a few examples.

And the oxidation numbers on the individual elements are tattooed on here in this example:

`stackrel(color(blue)(0))("Cu")_ ((s)) + stackrel(color(blue)(+V))("2N") stackrel(color(blue)(-II))("O"_ 3^(-)) ""_ ((aq)) + stackrel(color(blue)(+I))("4H"^(+))""_ ((aq)) -> stackrel(color(blue)(+II))("Cu"^(2+))""_ ((aq)) + stackrel(color(blue)(+IV))("2N") stackrel(color(blue)(-II))("O")_ (2(g)) + stackrel(color(blue)(+I))("2H")_ 2 stackrel(color(blue)(-II))("O")_ ((l))`

Is it balanced? What is reduced; what is oxidized?

This link shows you the common oxidation states for some elements and how to figure them out if necessary.