Question

If bromine atom is available in the form of say , two isotopes Bromine(z=35, A= 79) 49.7% and Bromine(z=35, A=81) 50.3%, Calculate the average atomic mass of bromine atoms.​

Answer 1

Required Answer:-

Average atomic mass is calculated by the average of the sum of isotopic mass × percentage composition.

We have:

• Isotopic mass A = 79
• Percentage composition = 49.7%
• Isotopic mass B = 81
• Percentage composition = 50.3%

Then by Formula:

Average atomic mass:

= 79 × 49.7 + 81 × 50.3 / 100

= 3926.3 + 4074.3 / 100

= 8000.6 / 100

= 80.006 u

Hence:

The average atomic mass of bromine atoms which is calculated as an average of them isotopes and their percentage composition:

$\huge{ \boxed{ \sf{ \orange{80.006 \: u}}}}$

Answer 2

Answer:

Required Answer:-

Average atomic mass is calculated by the average of the sum of isotopic mass × percentage composition.

We have:

Isotopic mass A = 79

Percentage composition = 49.7%

Isotopic mass B = 81

Percentage composition = 50.3%

Then by Formula:

Average atomic mass:

= 79 × 49.7 + 81 × 50.3 / 100

= 3926.3 + 4074.3 / 100

= 8000.6 / 100

= 80.006 u