* Hydrogen as an element: Hydrogen (H) is the simplest element, consisting of only one proton and one electron. So, in a single atom of hydrogen, there's just one atom.

* Hydrogen as a molecule: Hydrogen often exists as a diatomic molecule (H₂), meaning two hydrogen atoms are bonded together. In this case, there are two atoms in a molecule of hydrogen.

Let me know if you have any more questions about hydrogen!