Question

question.
what is average atomic mass?

the number of protons in the most abundant isotope
the sum of the atomic numbers of all isotopes
the weighted average of all isotopes of an element based on their percent abundance

Explanation:

To determine the correct definition of average atomic mass, we analyze each option:

• The first option refers to the number of protons (atomic number) of the most abundant isotope, which is not related to atomic mass.
• The second option involves summing atomic numbers (number of protons) of all isotopes, which is also not related to atomic mass.
• The third option correctly describes average atomic mass: it is a weighted average of the masses of all isotopes of an element, where the weights are the percent abundances of each isotope.

Answer:

C. The weighted average of all isotopes of an element based on their percent abundance