Final answer:
The oxidation number of nitrogen in NaNO3 is +5, calculated using the rules for assigning oxidation numbers and recognizing that oxygen typically has an oxidation number of -2.
Step-by-step explanation:
To determine the oxidation number of nitrogen (N) in NaNO3 (sodium nitrate), we can use a set of rules for assigning oxidation numbers combined with simple algebraic calculations. Each sodium ion has an oxidation number of +1. Oxygen has a consistent oxidation number of -2. There are three oxygen atoms, so together they have a total oxidation number of -6. The compound is electrically neutral, so the sum of the oxidation numbers of all the atoms must be zero. Using the formula x + 3(-2) = 0, we can solve for x, which is the oxidation number of nitrogen. The calculation leads to x = +6 - (-6), which simplifies to x = +5. Therefore, the oxidation number of nitrogen in NaNO3 is +5.