Question

smallest paticle in universe

Answer 1

The smallest particle in the universe is a proton , electron and a nueron that make up an atom

Answer 2

Well accordingly it was the "atom" which was the smallest particle in the universe, until it was proved wrong. An atom is divided further into protons, electrons and neurons. All of them revolving around a smaller particle called "nucleus." So, mostly nucleus is the smallest particle so far.