Question

Referring to the methods for calculating average atomic mass, which one is 'incorrect' ?

Mary
Jack
Alan

Answer 1

Answer:

I think Mary's and Alan's Methods are wrong. Jack is correct.  

Explanation:

(M1)(%)+(M2)(%)+(M3)(%)

You will be mulitplying the mass of Isotopes  by the percentages, (M1,2,3) are the isotopes. Then you just add the three to get the average.

There isn't any division involved.