Question

Ef bromine atom is avaible in the form of, soy two
isotopes To Br (51.6%) and 31 Br (54.3%). cabulate the
average atomic mass of bromine atom.​

Answer 1

Solution:

As per the given data,

• $\sf{Br_{35}^{79} = 51.6\%}$  
• $\sf{Br_{35}^{81} = 54.3\%}$

Average atomic mass is the sum of the product of their masses with their isotopic abundance.

$\implies\sf{Avg.atomic\: mass = 79 \times 51.6\% + 81 \times 54.3\%}$

$\implies\sf{Avg.atomic\: mass = 79 \times \dfrac{51.6}{100} + 81 \times \dfrac{54.3}{100}}$

$\implies\sf{Avg.atomic\: mass = 79 \times 0.516 + 81 \times 0.543}$

$\implies\sf{Avg.atomic\: mass = 40.76 + 43.98}$

$\implies\sf{Avg.atomic\: mass = 40.76 + 43.98}$

$\implies\boxed{\sf{Avg.atomic\: mass = 84.74 u}}$

Hence,

The average atomic mass of the bromine atom is 84.74u.