In one molecule of H₂O (water), there are two hydrogen atoms (H) and one oxygen atom (O).
To find out how many oxygen atoms are in one molecule of H₂O, you just need to look at the chemical formula. In this case, the subscript 2 in H₂O means that there are 2 hydrogen atoms and the subscript 1 after O means there is 1 oxygen atom.
Therefore, there is 1 oxygen atom in one molecule of H₂O.
