Question

What subatomic particle is not considered when calculating atomic

mass?
electrons
protons
neutrons

Answer 1

Electrons are not considered.

Step-by-step explanation:

An electron's mass is around 9.1 * 10^-31 kg, whereas the mass of protons and neutrons is around 1.7 * 10^-27 kg. Since electrons are about 1000x smaller than protons and neutrons, they are not considered to contribute significantly to the atomic mass.