Question

If bromine atom is available in the form of, say, two isotopes \(^{79}Br_{35}\) (49.7%) and \(^{81} Br_{35}\) (50.3%), calculate the average atomic mass of bromine atom.

Answer 1

It is given that two isotopes of bromine are \(^{79}Br_{35}\) (49.7%) and \(^{81} Br_{35}\) (50.3%). 

Then, the average atomic mass of bromine atom is = 7\(9 \times \frac{49.7}{100} + 81 \times \frac{ 50.3}{100}\)

= \(\frac{2926.3}{100} + \frac{4074.3}{100}\)

= \(\frac{8000.6}{100}\)
= \(80.006\) u