What is the total number of protons and neutrons in the nucleus of an atom?

1 Answer
Nov 8, 2016

Answer:

Well, to a good approximation it is the mass of that atom.

Explanation:

Protons and neutrons are massive particles. The combined number of #"protons"# and #"neutrons"#, of #"nucleons"#, constitute the mass of the atom. The #"electrons"#, while they do all the chemistry, are along for the ride, and do not make much contribution to the atomic mass. Certainly from a chemical perspective, their mass is negligible. From a physical perspective you will have to ask on the other forum.