What are the oxidation numbers for ClO-?
Here's what I got.
You're dealing with the hypochlorite anion,
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
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