Question

What information is needed to calculate the average atomic mass of an element?
A. the charge on each isotope
B. the relative abundance of its isotopes
C. the number of protons in each isotope
D. the toatal amount of the element in the sample or in nature

Answer 1

To calculate the average atomic mass of an element, the most relevant information is:

**B. the relative abundance of its isotopes**

The average atomic mass is calculated using the relative abundances of the element's isotopes and their respective atomic masses. The formula generally used is:

\[
\text{Average Atomic Mass} = \sum (\text{Fraction of isotope} \times \text{Mass of isotope})
\]

While knowing the number of protons and the charge of isotopes can provide context, they are not necessary for calculating the average atomic mass. The total amount of the element in the sample or in nature (D) is also not needed for this calculation.