Question

The need of the term average atomic mass​

Answer 1

Answer:

The average atomic mass of an element is the sum of the masses of its isotopes, each multiplied by its natural abundance (the decimal associated with percent of atoms of that element that are of a given isotope). ... An element does not have an absolute atomic mass.

Answer 2

So, the average atomic mass of an element (or just atomic mass )is the average of different mass number of the various isotopes of the elements in proportion with weight of that isotopes in 1 gram atom of that element