Question

The nutral isotopic abundance of10B is19.60% and 11B is 80.40% . The exact isotopic masses are10.13 and 11.009 respectively. Calculate the average atomic mass of boron (answer: 10.81)

Answer 1

The nutral isotopic abundance of $^{10}B$ is19.60% and ¹¹B is 80.40% . The exact isotopic masses are 10.13 and 11.009 respectively. we have to calculate average atomic mass of boron

we know, average atomic mass = {(mass of isotope $^{10}B$ × % abundance) + (mass of isotope ¹¹B) × % abundance)}/100

average atomic mass = (19.60 × 10.13 + 80.40 × 11.009)/100

= (198.548 + 885.1236)/100

= 1083.6716/100

= 10.836716 ≈ 10.83 amu