Competency #5

Learning Objective d

Question

Write down your answer to the following question:

Isotope Relative Abundance

Boron-10 20%

Boron-11 80%

Which of the following could be used to find the average atomic mass of boron?

  1. Average atomic mass = (10 + 11) / 2
  2. Average atomic mass = 11 (because it's the most common)
  3. Average atomic mass = (20*10 + 80*11) / 100
  4. The average atomic mass cannot be found from the information given
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