1. **Problem Statement:** Calculate the number of atoms in the formula Al2(PO4)3. 2. **Understanding the formula:** The formula Al2(PO4)3 means there are 2 aluminum (Al) atoms and 3 phosphate (PO4) groups. 3. **Counting atoms in each group:** Each PO4 group contains 1 phosphorus (P) atom and 4 oxygen (O) atoms. 4. **Calculate total atoms:** - Aluminum: $2$ atoms - Phosphorus: $3 \times 1 = 3$ atoms - Oxygen: $3 \times 4 = 12$ atoms 5. **Final answer:** The formula contains 2 Al atoms, 3 P atoms, and 12 O atoms.