Answer:
The correct answer is: Electron
Explanation:
Atom is the fundamental unit of matter that is composed of the subatomic particles electrons, protons and neutrons.
The nucleus of an atom contains protons and neutrons and are collectively known as the nucleons. Approximately 99.94% of the total mass of the atom is in the nucleus on the atom.
Therefore, the electrons has the least mass of about 9.11×10⁻³¹ kg which is approximately 1/1836 to the mass of the proton.