For example, does one atom of gold have a golden color?
Molecular properties such as melting point, conductivity, elasticity all require a multiplicity of atoms or molecules to be observed since each of those properties are defined interactions between the same particles. Color is different - when a photon hits an atom the atom's electrons are excited, the electron will fall back to it's unexcited (ground) state and when it does it emits a photon. This photon will not always have the same energy as the photon absorbed, when this is the case the rest of the energy was converted into thermodynamic energy (heat). Since the color of a wave of light can be defined by its energy then atoms can have "colors". This is a bit of an oversimplification but I hope it helps!
Edit: as @alchimista pointed out the color of a single atom will not likely represent the color of a sample of that element large enough to see. Also the light reflected from most atoms will likely cover the entire visible spectrum which will result in the same color of light being reflected as was used to illuminate it.