question_answer 51)

  A nuclide 1 is said to be the mirror isobar of nuclide 2 if Z1 = N2 and Z2 = N1. (a) What nuclide is a mirror isobar of? Na? (b) Which nuclide out of the two mirror isobars has greater binding energy and why?  

Answer:

                  By definition, a nuclide 1 is said to be mirror isobar of nuclide 2, if Z1 = N2 and Z2=N1. Now in 11Na23, Z1, =11, N1 = 23 - 11 = 12   Mirror isobar of 11Na23 is 12Mg23, for which Z2 = 12 and N2 = 23 - 12 = 11 As 12Mg23 contains even number of protons against 11Na23 which has odd number of protons, therefore 12Mg23 has greater binding energy than 11Na23