Final answer:
The average atomic mass calculator determines the weighted average mass of an element's isotopes, based on their abundance and individual masses, with the sum of these products resulting in the average atomic mass listed on the periodic table.
Step-by-step explanation:
The average atomic mass calculator is a tool used to calculate the weighted average mass of the different isotopes of an element, based on their natural abundance and individual atomic masses. To compute the average atomic mass, one must multiply the abundance of each isotope (converted from percentage to fraction form) by its atomic mass and then sum the results. For instance, chlorine with isotopes 35Cl and 37Cl having abundances of 75.77% and 24.23% respectively will have the average atomic mass calculated as follows:
- (0.7577 × 34.969 amu) + (0.2423 × 36.965 amu) = average atomic mass
This value is reflective of the weighted nature of the calculation, tending to be closer to the mass number of the most abundant isotope. Consequently, the periodic table lists the average atomic mass, representing the weighted average of the masses of all naturally occurring isotopes for each element.
Also, it is important to remember that atomic masses are not exactly the same as mass numbers due to the presence of neutrons and the nuances of atomic mass units (amu).