Abra has it pretty much right.

A very interesting question is whether or not collections of atoms have any objective reality.

I think they must do in some fashion, because the collection of atoms that constitutes a brain gives rise to the objectively real entity of consciousness.

Abra is wrong in one small detail which is that atoms are far from eternal. They didn't exist until quite a while after the big bang, and they are still being destroyed and created today in reactions with nuclear character.

The constituents of atoms, nucleons, specifically protons, may be eternal however.