Question

The previous two questions focused on stable isotopes, but there are substantially more unstable isotopes. For example, a very heavy isotope is iron-64, which undergoes beta decay until it becomes a stable isotope of nickel. Show this decay pathway with 2 steps of nuclear decay, identifying the nickel. Then explain that even though the atoms lose a part in the decay process, how does the mass not change? What did the atom lose?

a. 64Fe → 64Ni + β
b. The atom loses neutrons, but the mass does not change because the mass defect is converted into energy.
c. The atom loses electrons, which compensates for the mass loss.
d. The mass decreases as the atom loses protons.

Answer 1

Iron-64 undergoes beta decay to become a stable isotope of nickel. The decay pathway involves two steps, where iron-64 first decays into cobalt-64 and then into stable nickel-64. Despite losing a neutron during beta decay, the mass of the atom remains unchanged.

Step-by-step explanation:

Iron-64 undergoes beta decay to become a stable isotope of nickel. Beta decay is a type of nuclear decay where a neutron is converted into a proton and a high-energy electron, known as a beta particle, is emitted. In the case of iron-64, two steps of beta decay are involved:

1. Iron-64 decays by emitting a beta particle, becoming cobalt-64 which has an atomic number of 27 and a mass number of 64.
2. Cobalt-64 then undergoes another beta decay, emitting a second beta particle, and transforms into nickel-64 which has an atomic number of 28 and a mass number of 64. This is the stable isotope of nickel.

Even though the atoms lose a part (beta particles) in the decay process, the mass of the atom remains constant. This is because the mass of the beta particles is very small compared to the mass of the nucleus. The atom loses a neutron during the beta decay process, converting it into a proton, but the mass is conserved.