This is for oxidation numbers. I need to know how to show my work.

Ex: for NaClO, I have to find the oxidation number for Cl
I showed my work.
NaClO
+1+x+(-2)=0
+1+x-2=0
x-2=-1
x=-1+2
x=+1
Therefore, the oxidation number for chlorine in NaClO is +1.

Cl^-
I know that the oxidation number is -1 but I have no idea how to show my work.

3 answers

You are correct in both instances. The oxidation number for Cl in Cl^- is -1 because of the rule that says the oxidation number of an atom that is an ion is the charge on the ion. As another example, the oxidation number for Cl in ClO^- is still +1 because +1 on Cl + (-2) on oxygen leaves a -1 charge on the ClO ion.
Do you know how to show that using x? Show steps for it like I did with the first example?
No, I don't. It works on the others with an x as an unknown because of the rule that says that the sum of all the oxidation states in a compound is zero so you added all the states, plugged in x for the unknown, summed all to zero, and solved for x. i guess you could put
x = unknown oxidation state
charge on ion is -1
so x = -1 but that seems so obvious anyway.