Hello! I have just been wondering if each of the isotopes of an atom is determined by its proton (Z) and neutron number (N), then wouldn't these two numbers be enough to calculate the half-lives of them (given of course the masses of the proton and neutron also)? So, how does current nuclear physics determine the half-life of an isotope beforehand? What actual equations and calculations do you have to do, if theoretically those two numbers (Z & N) would be enough to determine it? Thank you.