Final answer:
Co-59 and Co-60 are isotopes of cobalt due to identical proton numbers but differing neutron counts. While Co-59 is stable, Co-60 is a radioactive isotope that decays into Ni-60 releasing energy and gamma rays.
Step-by-step explanation:
Co-59 and Co-60 are isotopes of cobalt because they have the same number of protons but a different number of neutrons. Cobalt-59 is stable with 27 protons and 32 neutrons, while Cobalt-60 is a synthetic, radioactive isotope with 27 protons and 33 neutrons, produced by the neutron activation of Co-59. When Co-60 undergoes ß-decay, it transforms into Ni-60, emitting an electron and gamma rays with decay energy in the MeV range.
The conservation of the total number of nucleons (protons plus neutrons) is evident since both before and after the decay, the sum remains 60 despite the change in the type of nucleon due to the decay process.