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

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.

girl imma just put my comment here because i need a couple point okurrttt

level 4 to level 2 : ))