the three stable isotopes of 9.051% , 0.27% and 9.22% the atomic masses of the three isotopes are 19.99 u , 20 .99 u and 21.99u respectively the avera

Monjur Alahi

the three stable isotopes of 9.051% , 0.27% and 9.22% the atomic masses of the three isotopes are 19.99 u , 20 .99 u and 21.99u respectively the average atomic mass of neon will be
A. 20.71u
B. 30.17u
C. 20.98u
D. 30.98u


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Correct Answer - a
The mass of the isotopes are `19.99` u `20.99` u and `21.99` u.
Their relative abundances are `90.51%,0.27 and 9.22%`
`therefore` Average atomic mass of neon
`m=(90.51xx19.99xx0.27xx20.99+9.22xx21.99)/((90.51+0.27+9.22))`
`=(2017.7)/(100)=20.17u`

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