Which subatomic particle has the least mass?

a. electron
b. proton
c. neutron
d. nucleus

Answer:   a.electron

The subatomic particle with the least mass is electron.

Explanation:

Atom is made up of three subatomic particles and the nucleus. The central part of the atom is occupied by the nucleus. The nucleus occupies minimal volume while most of the mass of the atom is contributed by the nucleus.

The nucleus contains sub atomic particles proton and neutron while the subatomic particle electron is present outside the nucleus.

The mass of electron is while proton has mass and neutron has a mass of

It is clear from these values that electron is very light when compared with proton and neutron. Proton and neutron has almost same mass.

6.4 cm (max) - 25 cm (min)