Hi Lissa,
ColorData
does support generating the periodic table for the "Atoms" named scheme.
ColorData[]
(* {"Gradients", "Indexed", "Named", "Physical"} *}
ColorData["Named"]
(* {"Atoms", "Crayola", "GeologicAges", "HTML", "Legacy", "WebSafe"} *)
ColorData["Atoms", "Image"] (* Generates periodic table *)