Question

the mass of which particle is disregarded when determining the mass of an atom?

○ subatomic particles

○ neutrons

○ protons

○ electrons

Explanation:

To determine which particle's mass is disregarded when calculating an atom's mass, we analyze the masses of subatomic particles:

• Protons and neutrons are located in the nucleus and have relatively large masses (proton: ~1 atomic mass unit (amu), neutron: ~1 amu).
• Electrons have a much smaller mass (about 1/1836 of a proton's mass). Due to this extremely small mass, the mass of electrons is generally ignored when determining the mass of an atom (which is mainly contributed by protons and neutrons in the nucleus).
• "Subatomic particles" is a general term, not a specific particle. Neutrons and protons contribute significantly to atomic mass.

Answer:

D. electrons