Question

What two particles have approximately the same mass?

Answer 1

The `"nucular"` particles: `"protons and neutrons"`.

Explanation:

The nuclear particles, protons and neutrons, are conceived to have a positive electronic charge, and a neutral charge respectively. The protonic mass is `1.672621898(21)xx10^(−27)*kg`.

And the neutron mass is `1.674927471(21)xx10^(−27)* kg`, so to a first approx. these masses are equal.

Data are from this site, and this site. Protons and neutrons engage in the strong nuclear force, which, at nuclear ranges, is stronger than the electrostatic forces of repulsion that operates between the protons.