If you are referring to the nitrate ion, NO3-, the oxidation number of oxygen would be O2- and nitrogen would be N5+. If you are talking about nitrogen trioxide NO3, the oxidation number of oxygen would be O2- and nitrogen would be N6+.
Edit: Nitrogen trioxide does not exist in its free state.
Nitrogens oxidation number is plus five. Oxygen's number is minus two.
In Ag NO3 the oxidation number of Ag (Silver) is 1+, the oxidation number of N (Nitrogen) is 5+, and the oxidation number of O (Oxygen) is 2-.
+2 for Copper
Manganese III's oxidation number is +3 and Nitrate's oxidation number is -1. Because you want the oxidation numbers to add together to make zero, you'd need to use Nitrate three times in the compound: Mn(NO3)3
Phosphorus in PCl5 Nitrogen in Nitrate (NO3-) ion
Nitrogens oxidation number is plus five. Oxygen's number is minus two.
In Ag NO3 the oxidation number of Ag (Silver) is 1+, the oxidation number of N (Nitrogen) is 5+, and the oxidation number of O (Oxygen) is 2-.
+2 for Copper
The oxidation number of nitrogen in the nitrate ion NO3- is 5
Manganese III's oxidation number is +3 and Nitrate's oxidation number is -1. Because you want the oxidation numbers to add together to make zero, you'd need to use Nitrate three times in the compound: Mn(NO3)3
Phosphorus in PCl5 Nitrogen in Nitrate (NO3-) ion
Na+ + NO3- --> NaNO3 The oxidation sum is zero for NaNO3.
The oxidation number of zinc (Zn) in Zn(NO3)2 is +2, while in Zn(OH)4^2-, it is also +2. Therefore, there is no change in the oxidation number of zinc.
It has to be Pb(NO3)2 with NaCl as Pb has a +II oxidation state and NO3 has -I oxidation state. The reaction is the following: Pb(NO3)2 +2NaCl ----> PbCl2 + 2NaNO3
-2 for each oxygen and +5 for nitrogen in NO3- ion
because the oxidation state of N decreases
The crisscross method uses the oxidation state (valence) of each element or ion. In this example, aluminum (Al) has an oxidation number of 3+. Nitrogen has an oxidation number of 3-. So, there really is no crisscross, because they are both the same, and they would combine to make aluminum nitride, AlN. If, however, you had aluminum, and nitrate ion (NO3^-), the crisscross would be to make the Al subscript a 1 and the NO3- subscript 3 to give Al(NO3)3.