To determine the number of hydrogen atoms in one formula unit of ammonium nitrate (\( \text{NH}_4\text{NO}_3 \)), let's examine the chemical formula in detail.
1. Identify the parts of the chemical formula: Ammonium nitrate is made up of the ammonium ion (\( \text{NH}_4^+ \)) and the nitrate ion (\( \text{NO}_3^- \)).
2. Focus on the ammonium part (\( \text{NH}_4 \)) of the formula since we need to find the number of hydrogen atoms:
- Within the ammonium ion (\( \text{NH}_4 \)), "N" represents one nitrogen atom.
- "H4" indicates that there are 4 hydrogen atoms bound to the nitrogen atom.
3. The nitrate part (\( \text{NO}_3 \)) consists of one nitrogen atom and three oxygen atoms, but it does not contribute any hydrogen atoms.
Since we are only interested in hydrogen atoms, we conclude that:
In one formula unit of ammonium nitrate (\( \text{NH}_4\text{NO}_3 \)), there are 4 hydrogen atoms.
Thus, the correct answer is:
B. 4 atoms
