* Water molecule formula: H₂O (2 hydrogen atoms and 1 oxygen atom)

* Two water molecules: 2 x (H₂O) = 2 x (2 hydrogen atoms + 1 oxygen atom)

* Total atoms: 2 x 2 hydrogen atoms + 2 x 1 oxygen atom = 4 hydrogen atoms + 2 oxygen atoms = 6 atoms

Therefore, 6 atoms combined form two water molecules.