To determine the number of atoms in the formula Na2HPO4, we can break down the formula into its individual elements:
- Na (Sodium): 2 atoms
- H (Hydrogen): 1 atom
- P (Phosphorus): 1 atom
- O (Oxygen): 4 atoms
Now, we add the number of atoms together:
2 (Na) + 1 (H) + 1 (P) + 4 (O) = 8 atoms.
Thus, the total number of atoms represented in the formula Na2HPO4 is 8.
The correct answer is A. 8.