Answer:
There are more protons in neutrons in a stable isotope.
Step-by-step explanation:
There are more protons in a stable isotope because protons are more stable than nuetrons. Protons are lighter, while neutrons tend to be able to decay into a proton, electron to conserve charge, and an electron anti-neutrino lepton number. Because these things have a total mass that is less than the original nuetron, in the process it results in emitting energy. Overall, a proton has the lowest mass of any baryon; there is nothing left that is could possibly decay into unless the baryon number is destroyed. Which by laws and theories, seems to not be permitted. To give more information, the first two elements, hydrogen and helium, have stable isotopes where there is one less neutron than the number of protons. All of the elements do not contain a stable isotope that consists of this property.