If a bromine atom is available in the form of two isotopes 74Br35(49.7%) and 81Br35(50.3%), then the average atomic mass of the bromine atom is [[1]].

If a bromine atom is available in the form of two isotopes

74

Br

35

(49.7%) and

81

Br

35

(50.3%), then the average atomic mass of the bromine atom is 80.006.

We know that,

$\mathit{average\; atomic\; mass\; of\; br}$

$=\mathit{atomic\; mass\; of}{\mathit{Br}}_{35}^{74} \times \frac{\mathit{percentage}}{100}+\mathit{ atomic\; mass\; of }{\mathit{Br}}_{35}^{81}\times \frac{\mathit{percentage}}{100}$

$=79\times \frac{49.7}{100}+81\times \frac{50.3}{100}$

$=80.006$

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