Most abundant nuclide...?

Question

In each of the following pairs, which nuclides would you expect to be the more abundant in nature

a) 19/9 F or 18/9 F

b)80/34 Se or 81/34 Se

c) Iron-56 or iron-57

d) tin-118 or antimony-118

Justify the choices

Thank you for the help

10 points

Answer 1

a) 19/9 F  100%                         18/9 F - Synthetic radioisotope

b) 80/34 Se  49.61%        81/34 Se - not in existence

c) Iron-56    91.72%       iron-57     2.2%

d) tin-118     24.22% and antimony-118 - not in existence