Can you reduced atom to nothingness?

The answer is NO. OldProf discusses fission, but even that does NOT create nothingness, as he states there are still the daughter atoms to contend with.

--- Not even a black hole does this. Material, including atoms, is sucked into a blackhole and there is gamma radiation emmitted with the "destruction" of the matter by the blackhole, so again, not nothingness, but gamma rays.

There us NO process that does will do what you are asking about.

To nothingness? Not likely. But we can and do reduce atoms into other smaller atoms through nuclear fission. And that let's loose a lot of energy plus the so-called daughter atoms created by the fission.