Here's how to break down the calculation of atoms in (NH₄)₃PO₄:

1. Identify the Elements:

* N (Nitrogen)

* H (Hydrogen)

* P (Phosphorus)

* O (Oxygen)

2. Count the Atoms per Molecule:

* N: 3 (from the subscript outside the parentheses) * 1 (from inside the parentheses) = 3 atoms

* H: 3 (from the subscript outside the parentheses) * 4 (from inside the parentheses) = 12 atoms

* P: 1 atom

* O: 4 atoms

3. Total Atoms:

3 (N) + 12 (H) + 1 (P) + 4 (O) = 20 atoms

Therefore, there are 20 atoms in one molecule of (NH₄)₃PO₄.