During your research, did you come across the masses of the various subatomic particles we discuss in chemistry? How does the mass of the proton relate to the mass of a neutron and electron? Which atoms contribute the greatest amount of mass to an atom? After you research these questions, look at this sentence about molecular mass and see if you can find where some clarification is needed. The sentence is written as such "Molecular mass is the mass of one molecule which is equal to the sum of the mass of electrons and neutrons".