Answer:
NH₄NO₃
Step-by-step explanation:
In salt naming, the cation is named first, then you must put the name of the anion. In the same way when you are writting the formula. Also, the global charge of a salt is always 0.
Thus, we must write each ion and its charge:
Ammonium: NH₄⁺
Nitrate: NO₃⁻
As both ions have the same charge, the formula is:
NH₄NO₃
The cation first and then the anion.