The mass numbers of three istopes of an element are `10,12 and 14` units .Their precentage abundance is `80,15 and 5` respectively .What is the atomic weight of the element ?

Explanation

The precentage abundences of isotopes are `80,15, and 5` .This is `16:3:1`
Total of the ratio `= 16 + 3 + 1 = 20`
`"Average weight" = (% "abundance" xx" atomic weight")/("Total of ratio" )`
`"Average weight" = (10 xx 16 + 12 xx 3 + 14 xx 1)/(20) = 10.5`
Thus the average atomic weight is `10.5` unit.