question_answer 57)

  Nuclei with magic no. of proton Z =  2, 8,20,28,50,52 and magic no. of neutrons N=2,8, 20,28,50, 82 and 126 are found to be very stable, (i) Verify this by calculating the proton separation energy Sp for 120Sn (Z = 50) and 121Sb = (Z = 51).The proton separation energy for a nuclide is the minimum energy   required to separate the least tightly bound proton from a nucleus of that nuclide. It is given by  (ii) What does the existence of magic number indicate?  

Answer:

                  (i)The proton separation energy is given by                                        ?(i)                 For Sn,                 and                                        Similarly,   Since , therefore S n nucleus, which was to be proved. (ii) The existence of magic numbers indicates the shell structure of nucleus similar to the shell structure of an atom. It also accounts for the peaks in Binding energy/nucleon curve.