Decay of Pb-212

As an example, consider the radioactive isotope of lead ²¹²Pb. It contains 82 protons and 130 neutrons. It decays by the process n → p + e^- + ν[bar] . The newly created proton is held inside the nucleus by the strong nuclear force, so the new nucleus contains 83 protons and 129 neutrons. Having 83 protons makes it the element bismuth, so it will be an atom of ²¹²Bi.