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An element X has the following isotopic ...

An element X has the following isotopic composition `.^(200)X : 90%, .^(199)X: 8.0%, .^(202)X:2%` . The Weighed average atomic mass of naturally occurring element X is closet to

A

199 a.m.u.

B

200 a.m.u.

C

201 a.m.u.

D

202 a.m.u.

Text Solution

Verified by Experts

The correct Answer is:
B
Average atomic mass, `overset(-)(A)=Sigmaf_(i)A_(i)`
(`f_(i)`=fractional abundance, `A_(i)`=atomic mass)
Atomic mass
`=0.90xx200+0.08xx199+0.02xx202`
`=180+15.92+4.04~~200`
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