The relative atomic mass of a naturally occurring lithium consisting of 90% \(^7 _3\)Li and \(^6 _3\)10% Li is
-
6.9
- 7.1
- 6.2
- 6.8
The correct answer is: A
Explanation
R.A.M = m\(_1 \alpha_1\) + m\(_2 \alpha_2\)
= 7(90/100) + 6(10/100)
= 6.3 + 0.6
= 6.9
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