Atomic weight of ` Ne` is ` 20.2 Ne` is a mixuture of ` Ne^(20)` and ` Ne^(22)`. Relative abunduance fo heavior isotope is :

Options

A. `1:9`
B. `9:1`
C. `7:3`
D. `8:2`

Answer

B

Explanation

Let `W%" of "Ne^(20)=x`
`W%" of "Ne^(22)=100-x`
`20.2=(xx20+(100-x)22)/(100)`
`2020=20x+2200-22x`
`2x=2200-2020`
`2x=180`
`x=90%`
`w%" of "Ne^(20)=90%`
`w%" of "Ne^(22)=100-90=10%`
`N^(20):N^(20)=90:10=9:1`