Final answer:
There seems to be a typographical error in the chemical formula provided. The correct formula for ammonia is NH₃, which contains one atom of nitrogen. There is no known stable compound with the formula NHO₃.
Step-by-step explanation:
The question asks how many atoms of nitrogen are in the substance with the chemical formula NHO₃. This chemical formula appears to be incorrect, possibly due to a typographical error, as there is no known stable compound with this formula.
In chemical formulas, subscripts are used to represent the number of atoms of each element present in the molecule. For instance, the compound dinitrogen trioxide has the formula N₂O₃, indicating that there are two atoms of nitrogen. In the case of ammonia, represented by NH₃, it is clear that there is one atom of nitrogen (N) in this molecule.