Answer:
Average atomic mass is the weighted average of all the Isotopes in an element.
Step-by-step explanation:
The isotopes of an element are those in which their atomic numbers (that is, the number of protons) are equal, but the number of neutrons is different. The same chemical element may consist of different atoms, that is, different isotopes.
The atomic mass of an element is the weighted average mass of its natural isotopes. Therefore, the atomic mass of an element is not an integer. This means that the atomic masses of the chemical elements are usually calculated as the weighted average of the masses of the different isotopes of each element taking into account the relative abundance of each of them.
Finally, Average atomic mass is the weighted average of all the Isotopes in an element.