Consider the following reaction equation: \(2NO_{(g)} + O_{{2}{(g)}} \to 2NO_{{2}{(g)}}\). What is the change in the oxidation number of nitrogen?

The oxidation number is a number that represents the number of electrons an atom has gained or lost in a molecule. In the given reaction, the oxidation number of nitrogen changes from +2 to +4. At the beginning of the reaction, nitrogen in NO has an oxidation number of +2, while in NO2 it has an oxidation number of +4. This means that nitrogen has gained two electrons and undergone oxidation. To understand why this is happening, we need to look at the reaction. The reactants are NO and O2, and the product is NO2. The oxygen atoms in the reactants have an oxidation number of 0, while in the product they have an oxidation number of -2. This means that each oxygen atom has gained two electrons and undergone reduction. Since nitrogen has not gained or lost any electrons in the reaction, it is not undergoing reduction or oxidation, but it is participating in the reaction by forming bonds with the oxygen atoms. The change in oxidation number of nitrogen from +2 to +4 is a result of sharing two electrons with each oxygen atom in the product. Therefore, the correct answer is "+2 to +4".