Question

which subatomic particles contribute the most to the mass of an atom? electrons only protons and electrons neutrons and electrons protons and neutrons

Explanation:

Protons and neutrons are located in the nucleus of an atom and have relatively large masses compared to electrons. Electrons have a very small mass and contribute negligibly to the overall mass of an atom. So, protons and neutrons contribute the most to the mass of an atom.

Answer:

Protons and neutrons