Answer
The binding energy curve (it is a plot of binding energy per nucleon against mass number) shows that in the high mass number range(>100) binding energy per nucleon sharply decreases with mass number, showing that the heavier nuclei are less stable. Thus the nuclei of heavy elements like U, Th have comparatively low binding energy and they tend to split into more stable smaller nuclei. Thus, the heavy nucleus undergoes nuclear fission.
Work Step by Step
The binding energy curve (it is a plot of binding energy per nucleon against mass number) shows that in the high mass number range(>100) binding energy per nucleon sharply decreases with mass number, showing that the heavier nuclei are less stable. Thus the nuclei of heavy elements like U, Th have comparatively low binding energy and they tend to split into more stable smaller nuclei. Thus, the heavy nucleus undergoes nuclear fission.
