Final answer:
To calculate the average atomic mass of an element, you need to know the relative abundance and mass of each isotope.
Step-by-step explanation:
To calculate the average atomic mass of an element, you need to know the relative abundance of each isotope and the mass of each isotope. The formula for calculating the average atomic mass is:
Average Atomic Mass = (%Abundance of Isotope 1 * Mass of Isotope 1) + (%Abundance of Isotope 2 * Mass of Isotope 2) + ...
For example, let's calculate the average atomic mass of chlorine. Chlorine has two isotopes: chlorine-35 with a mass of 35 amu and chlorine-37 with a mass of 37 amu. The natural abundance of chlorine-35 is 75.76% and the natural abundance of chlorine-37 is 24.24%. Using the formula, the average atomic mass of chlorine is:
(0.7576 * 35 amu) + (0.2424 * 37 amu) = 35.45 amu.
Use the formula: Average Atomic Mass = (%Abundance of Isotope 1 * Mass of Isotope 1) + (%Abundance of Isotope 2 * Mass of Isotope 2) + ...