What the difference between monatomic and colloidal gold?

The answer is that they are altogether different. In a colloid, there is no necessity that the scattered gold be as disengaged iotas. Colloidal gold is as nanoparticles, each having numerous iotas of gold. Note that gold is normally monoatomic, and does not tie to itself synthetically, not at all like oxygen, which ties in sets to accomplish lively soundness.