Determining the number of atoms in a molecule like ammonium phosphate, (NH₄)₃PO₄, requires understanding chemical formulas and a bit of simple math. Let's break it down step-by-step.
Understanding the Chemical Formula
The formula (NH₄)₃PO₄ represents ammonium phosphate. Let's dissect it:
- (NH₄): This is the ammonium ion (NH₄⁺). Notice it's in parentheses with a subscript 3. This means there are three ammonium ions in the molecule.
- PO₄: This is the phosphate ion (PO₄³⁻).
Counting the Atoms
Now, let's count the atoms in each part of the molecule:
1. Ammonium Ion (NH₄):
- Nitrogen (N): 1 atom
- Hydrogen (H): 4 atoms
Since there are three ammonium ions, we multiply the number of atoms in each ammonium ion by 3:
- Nitrogen (N): 1 atom/ion * 3 ions = 3 atoms
- Hydrogen (H): 4 atoms/ion * 3 ions = 12 atoms
2. Phosphate Ion (PO₄):
- Phosphorus (P): 1 atom
- Oxygen (O): 4 atoms
3. Total Atom Count:
Adding up all the atoms from the ammonium ions and the phosphate ion, we get:
- Nitrogen (N): 3 atoms
- Hydrogen (H): 12 atoms
- Phosphorus (P): 1 atom
- Oxygen (O): 4 atoms
Total number of atoms: 3 + 12 + 1 + 4 = 20 atoms
Therefore, there are a total of 20 atoms in one molecule of ammonium phosphate, (NH₄)₃PO₄.
Key Concepts to Remember
- Subscripts: The small numbers written below and to the right of a symbol indicate the number of atoms of that element in a molecule or ion.
- Parentheses: Parentheses in a chemical formula mean that everything inside them is multiplied by the subscript following the parentheses.
Understanding these concepts is crucial for correctly determining the number of atoms in any chemical compound. This method can be applied to any chemical formula you encounter.
