Question

Put the following compounds in order of INCREASING oxidation number of N:

N2H4, NO3-1, N2, NH3 ?

Answer 1

Do you know how to determine the oxidation number for N in these compounds?
I'll do the first two for you.
#1 rule. Compounds or elements have a charge of zero.
#2 rule.The oxidation state of all of the elements in the material must add to zero (if it's a compound) or to the charge on the ion if it's an ion.

For N2H4. H is +1 so 4 of those = +4. That makes 2N = -4 or each N must be -2.
How do you know H is +1. It's ALWAYS +1 except in hydrides such as LiH, NaH, KH, AlH3, etc.

For NO3^-. O is -2 each and 3*-2 = -6 total. You want to leave a -1 charge on the ion; therefore, N must be +5. You can check that to make sure.
N = +5
O = 3*-2 = -6
+5 + )-6) = -1 which is the charge on the ion.
How do I know O is -2. It is ALWAYS -2 except in peroxides or superoxides such as H2O2 (it's -1 in peroxides), K2O2 (another peroxide) or KO2 (it's -1/2 in superoxides).
Now you do the other two. Clearly explain why you're stuck if you need more help.