To determine the number of oxygen atoms in one formula unit of ammonium nitrate (NH₄NO₃), follow these steps:
1. Identify the composition of ammonium nitrate:
- The chemical formula for ammonium nitrate is [tex]\( NH_4NO_3 \)[/tex].
2. Break down the formula into its constituent ions:
- Ammonium ion: [tex]\( NH_4^+ \)[/tex]
- Nitrate ion: [tex]\( NO_3^- \)[/tex]
3. Examine the nitrate ion (NO_3^-):
- The nitrate ion contains one nitrogen (N) atom and three oxygen (O) atoms.
4. Consider the ammonium ion (NH₄^+):
- The ammonium ion contains one nitrogen (N) atom and four hydrogen (H) atoms. It does not have any oxygen atoms.
5. Sum the number of oxygen atoms:
- Since the ammonium ion (NH₄^+) has no oxygen atoms and the nitrate ion (NO₃^-) has three oxygen atoms, the total number of oxygen atoms in one formula unit of ammonium nitrate (NH₄NO₃) comes solely from the nitrate ion.
Therefore, in one formula unit of ammonium nitrate, [tex]\( NH_4NO_3 \)[/tex], there are a total of 3 oxygen atoms.
The correct answer is A. 3 atoms.
