What is the two most massive particles in an atom?

In order from heaviest to lightest: Higgs Boson, Top Quark, Z0, W+,-, Bottom quark, and Tau lepton. All others are less than 1.7 GeV and are not worth mentioning, are composite particles made up of quarks and too numerous to mention, or are predicted to exist if certain models are correct but have not been (and probably cannot be) observed.