Question

Why does the binding energy per nucleon decreases with increase in mass number for heavy nuclei like 235u?

Answer 1

BE/A reduces for particles greater than few Fermi metres since nuclear force is short ranged, for heavier nuclei BE/A is very low and the nucleus is unstable

Answer 2

Explanation:

Due to increase in mass no. increases protons thus , repulsive force increase and the nucleus becomes unstable due to which binding energy reduces.