Which of the following is closest to the atomic mass of boron?

• A. 10.81
• B. 14.01
• C. 9.01
• D. 12.01

Answer: (A)

Verified step by step guidance

1. Understand that the atomic mass of an element is the weighted average of the masses of its naturally occurring isotopes, measured in atomic mass units (amu).
2. Recall that boron has two main isotopes: boron-10 and boron-11, with atomic masses close to 10 amu and 11 amu respectively.
3. Recognize that the atomic mass listed on the periodic table reflects the average mass based on the relative abundance of these isotopes.
4. Compare the given options (14.01, 9.01, 12.01) to the known approximate atomic mass of boron, which is around 10.8 amu.
5. Identify that 10.81 is closest to the actual atomic mass of boron, confirming it as the correct choice.