The relative atomic mass of natural lithium is 6.95 it consist of two isotopes of relative masses 6.02 7.02 calculate the natural abundance of the isotopes

1 answer

Fractional abundance of Isotope 1 = x
Fractional abundance of Isotope 2 = (1 - x)

The average mass in this case is 6.95

=> (Mass 1)*(Abundance 1) + (Mass 2)*(Abundance 2) = 6.95
=> 6.02*x + 7.02*(1-x) = 6.95
=> 7.02 - 6.95 = x
=> x = 0.07
=> 1- x = 0.93

Hence, Isotope 1 is 7% while Isotope 2 is 93%