Question

The natural isotopic abundance of 10B is 19.60% and 11B is 80.40%. The exact isotopic masses are 10.13 and 11.009 respectively. Calculate the average atomic mass of boron.​

Answer 1

Answer:

The answer is 10.81 u

Explanation:

Relative abundance of 10B isotope =  19.60%

Relative abundance of 11B isotope =   80.40%

Average atomic mass= (Mass of isotope 1) x (Relative abundance of 10B isotope)  + (Mass of isotope 2) x (Relative abundance of 11B isotope / 100

= (10 x 19 ) + (11 x 81 ) / 100

= 190 + 891 / 100

= 1081/100

= 10.81 u

Thus the average atomic mass of boron is 10.81 u.