Average Atomic Mass and Percent Abundance

Assume that you have two grades in a class. One is a test grade and you earned a one hundred percent. You did excellent. In fact, you were so confident about the material, you did not even bother to do the homework. If the teacher averaged your grade weighing homework and test scores equally, you would only earn a fifty percent. Does that seem fair? Do you think that each grading category should count for the same percentage of your grade? In this topic, you will explore at how the atomic mass of an element is calculated with the same considerations.

Essential Question

• How does average atomic mass reflect the relative abundance of an isotope for an element?