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.
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.