The binding energy per nucleon (BEPN) is a measure of the average binding energy that holds a nucleon (proton or neutron) within the nucleus of an atom. Higher BEPN values indicate greater stability of the nucleus.
In the case of strontium-90 (Sr-90) and yttrium-90 (Y-90), Sr-90 is the parent isotope that decays into Y-90. The difference in their binding energy per nucleon can be attributed to the specific nuclear properties and arrangement of nucleons in each isotope.
The binding energy of a nucleus is influenced by the interplay between the attractive nuclear forces (strong force) that hold the nucleons together and the repulsive electrostatic forces between the protons. When a nucleus undergoes radioactive decay, it typically transforms into a more stable configuration, resulting in a change in the binding energy per nucleon.
In this case, the binding energy per nucleon of Sr-90 is higher than that of Y-90, indicating that Sr-90 is relatively more stable. This can be understood by considering the nuclear structure and composition of the isotopes.
Sr-90 has 38 protons and 52 neutrons, while Y-90 has 39 protons and 51 neutrons. As the number of protons increases in Y-90 compared to Sr-90, there is a greater electrostatic repulsion between the protons. This leads to a slightly lower binding energy per nucleon in Y-90.
The specific arrangement of nucleons and their interaction within the nucleus can result in variations in the binding energy per nucleon, even for isotopes with similar masses. Small differences in the number of protons and neutrons can affect the overall stability and binding energy of a nucleus.
It's important to note that the difference in binding energy per nucleon between Sr-90 and Y-90 is relatively small. Nevertheless, it illustrates the subtle variations that can occur in nuclear stability due to differences in proton and neutron numbers.