Boron occurs naturally in two isotopes ¹⁰B and ¹¹B. The standard atomic mass of Boron is 10.811. What are the percentage abundances of ¹⁰B and ¹¹B? (Given: exact mass of ¹⁰B = 10.01294 amu and ¹¹B = 11.00931 amu) A) 50% and 50% B) 60% and 40% C) 70% and 30% D) 90% and 10% E) 20% and 80%

Question

Quizplus · Accepted Answer

The average atomic mass of boron (10.811 amu) is closer to the mass of ¹¹B (11.00931 amu), indicating that ¹¹B is more abundant. Solving the equation 10.01294x + 11.00931(1-x) = 10.811 gives approximately 20% for ¹⁰B and 80% for ¹¹B.

Boron Occurs Naturally in Two Isotopes 10B and 11B

Boron Occurs Naturally in Two Isotopes ¹⁰B and ¹¹B