Question

Question 20 5 pts A Pt-204 atom (platinum-204) has a nucleus with 78 protons and an atomic mass of 203.980762 u. What is the nuclear binding energy per nucleon in this atom? 1.72 MeV 1603 MeV 20.6 MeV 12.7 MeV 7.86 MeV

Answer 1

Mass of 78 protons = 78 x 1.00728 u = 78.5678 u.

Mass of ( 204 - 78 ) = 126 neutrons = 126 x 1.00866 u = 127.09116 u.

Hence, total mass of all nucleons = 78.5678 u + 127.09116 u ~ 205.66 u.

Atomic mass of Pt - 204 is 203.980762 u.

Hence, mass defect = 205.66 u - 203.980762 u ~ 1.68 u.

Hence, binding energy = 1.68 x 931.5 MeV ~ 1565 MeV.

Hence, binding energy per nucleon = 1565 MeV / 204 ~ 7.67 MeV.

Hence, correct option is : 7.86 MeV ( closest value to the calculated one ).