Color is the wave length of light you can see. Red is one wavelength, blue another, infra red and ultra violet yet another. But you can't see those last two.
Molecules have no color because they are smaller then the shortest length wave of light you and I can see.
Think about dropping a stone in a quiet pond. Think of the waves that are created. If they bump into a large obstacle they are reflected back. If they hit a tiny one, like a thin blade of grass sticking out of the water, they just flow around.
Gold is golden because a whole lot of gold atoms bunched together reflect a yellowish range of light. Gold the material is gold colored. A single gold atom does not have color.
So if I'm a gold atom, and I absorb some photons, a bunch pass through me, and some get reflected - and the photons that are reflected from me over a period of time happen to be average out to something a cone cell in the retina would interpret as gold- couldn't I say that I'm gold-colored? In other words, replacing the billion-atom aggregation with a simple time series?
It seems to me it's an argument about semantics, not physics.
that's not the case, the physics in fact is very different for a single atom than for a lump of metal.
A single atom has very specific set of electron energies as a consequence of the electrons being confined to the area around the nucleus. This means that it can only absorb or emit photons with energies corresponding to the spacings between any two energy levels (and the absorption/emission must be accompanied by a jump/fall of an electron between corresponding energy levels. Any type of atom will thus have a secific pattern of absorption/emission peaks, this is incidentally how we can tell the composition of stars and dust clouds in distant galaxies.
For a lump of metal, a good approximation is to consider the electrons as being able to freely roam throughout the entire crystal. As a consequence, when they are excited by an incoming photon (of any energy), they immediately relax back to their original state, emitting the photon again at the same energy. This is why metal films act as mirrors and why metals in general are shiny. As for the goldish color of Gold, that has to do with some relativistic effects which I don't understand (yet ;-) ). I believe the same is true for Copper.
I think there is some terminology confusion. The image is not a "photo" - it is not a recording of emitted light. Hence the colors used to display the image for us have nothing to do with the color (reflected wavelengths) of the molecules.
Ah but protons aren't particles... except some times they are, other times they are a waves. The bottom line is individual atoms don't reflect protons.
Molecular absorption and emission of photons is one mechanism by which color is created. For example, the color of water is caused by molecular absorption.
i'm hoping the guy was being sarcastic but...