Question

An element has isotopic species A and B each with a mass number 39 and 40 respectively. The percentage of A is 60% and B is 40% for an isotopic element X. Calculate the relative atomics mass of X.

Answer 1

R.A.M = (39×60)+(40×40)   
                      100
              2340 + 1600     
                    100
          = 3940    
              100
          =39.40