Question

What are the oxidation numbers for ClO-?

Answer 1

Here's what I got.

Explanation:

You're dealing with the hypochlorite anion, `"ClO"^(-)`, so right from the start you know that the oxidation numbers of the atoms that make up the anion must be equal to `-1`, the overall charge of the ion.

This means that you can write

`ON_"chlorine" + ON_"oxygen" = -1`

Now, oxidation numbers are all about electronegativity. As you know, oxidation numbers are assigned with one concept in mind - that more electronegative atoms will take the bonding electrons from the bond it has with a less electronegative atom.

When oxygen is pairred with a less electronegative atom, its oxidation state is always equal to `color(blue)(-2)`.

In this case, oxygen is indeed more electronegative than chlorine, so you can say that

`ON_"chlorine" + (color(blue)(-2)) = -1`

This means that you have

`ON_"chlorine" = -1 + 2 = color(blue)(+1)`

The oxidation numbers for the atoms that make up the ion are

`stackrel(color(blue)(+1))("Cl") stackrel(color(blue)(-2))("O"^(-))`