* 3: This represents the number of molecules of water (H₂O).

* H₂O: This represents one molecule of water.

Atoms per molecule:

* Hydrogen (H): There are 2 hydrogen atoms in each water molecule.

* Oxygen (O): There is 1 oxygen atom in each water molecule.

Total atoms:

* Hydrogen: 3 molecules * 2 H atoms/molecule = 6 hydrogen atoms

* Oxygen: 3 molecules * 1 O atom/molecule = 3 oxygen atoms

Therefore, in 3 H₂O, there are 6 hydrogen atoms and 3 oxygen atoms.