Which of the following subatomic particles has the smallest mass?

Electrons have the smallest mass among subatomic particles. To provide some context, protons and neutrons, which reside in the nucleus of an atom, are significantly more massive than electrons. Specifically, a proton has a mass of approximately 1.67 × 10^-27 kg, and a neutron is about the same, whereas an electron has a mass of approximately 9.11 × 10^-31 kg.

Nuclei, which are composed of protons and neutrons, have an even greater mass as they include the combined mass of these particles. Therefore, when considering individual subatomic particles, electrons are the lightest, making them crucial in various atomic and molecular interactions, such as chemical bonding and electricity. This is a fundamental concept in understanding atomic structure and the behavior of matter.