An investigator who hoped to learn something about what scientists took the atomic theory to be asked a distinguished physicist and an eminent chemist whether a single atom of helium was or was not a molecule. Both answered without hesitation, but their answers were not the same. For the chemist the atom of helium was a molecule because it behaved like one with respect to the kinetic theory of gases. For the physicist, on the other hand, the helium atom was not a molecule because it displayed no molecular spectrum.
Thomas Kuhn in The Structure of Scientific Revolutions
Thomas Kuhn in The Structure of Scientific Revolutions
A high school student would say no, because by definition a molecule has more than one atom.
That depends entirely on your definition (which is the point of the quote I guess), I’ve heard people use it both ways.