How many protons are in hydrogen - 2

The number of protons in the nucleus of an atom determines

what element the atom is an atom of.

If there's one proton in the nucleus of an atom, then the atom

is an atom of Hydrogen.

If there's any other number of protons other than one in the nucleus

of an atom, then the atom is an atom of some other element. It's not

an atom of Hydrogen.

If you say you have an atom of Hydrogen, then I know there's exactly

one and only one proton in its nucleus. If you call it Hydrogen-2, I know

you must be talking about the Atomic Weight of the nucleus, and there

must be a neutron in there too.

If you called it Hydrogen-37, I would know that there would still be exactly

one proton there, lost in a crowd of 36 neutrons.