Welcome to the Community College of the Air Force (CCAF). Our college is a federally-chartered degree-granting institution that serves the United States Air Force's enlisted total force.
Isotopes of an element have nuclei with the same number of protons (the same atomic number) but different numbers of neutrons. Therefore, isotopes have different mass numbers, which give the total number of nucleons-the number of protons plus neutrons.
Isotopes are elements with different numbers of neutrons, thus having different masses. But isotopes of the same element always have the same number of protons, otherwise they'd be a different element. Nucleons are the protons and neutrons combined. Daltons are the fundamental unit of mass in Alchemy. Nucleons (protons and neutrons) all have a mass of one Dalton.