The mass number of three isotopes of an element are 10,12,14 units. Their percentage aboundance is 80,15 and 5 units respectively. What is the atomic weight of the element?

Explanation

Percentage abundances of Isotopes =80,15,5 ratio of percentage abundances of Isotopes =16:3:1 The total ratio `= 16 +3 +1 = 20`
avg. Awt `=(sum "ratio of % abundance" xx "Atomic weights")/("Total ratio")`
`= (10 xx 16 +12 xx 3 +14 xx 1)/(20) = 10.5`
The average Atomic weight `=10.5`