Question

which subatomic particles contributes the least to the mass of an atom? electrons protons neutrons

Explanation:

To determine which subatomic particle contributes the least to an atom's mass, we recall the masses of subatomic particles:

• Protons: ~1 atomic mass unit (amu).
• Neutrons: ~1 amu.
• Electrons: ~0.00054858 amu (negligible compared to protons/neutrons).

Electrons have a much smaller mass than protons or neutrons, so they contribute the least to an atom’s mass.

Answer:

Electrons