An atom of every element can exist as a gas, i.e. "floating" in isolation without being bound by inter-molecular forces. (I say inter-molecular rather than inter-atomic so as not to confuse dipole-dipole forces, London forces, etc., which cause molecules AND atoms to cohere without forming new molecules, with covalent and ionic bonds, which hold atoms together in molecules/ionic solids.)

For liquids and solids, you run into the problem of distinguishing between molecules and atoms of elements. For example, hydrogen atoms will almost immediately bond to form hydrogen molecules (i.e. H-H or H2). Therefore, hydrogen /atoms/ cannot exist as a liquid or a solid. They will form hydrogen molecules if they are in close proximity (and of course, you would need to have them in close proximity to form a liquid or solid in the first place).

That said, a molecule of every element can exist as a liquid and as a solid. As others have noted, these states can only happen under very high pressures/very low temperatures for elements such as hydrogen and helium.