The atomic mass of an element is the weighted average of what?

1 Answer
May 29, 2016

Answer:

...Of the mass of the individual isotopes.

Explanation:

Most elements have a number of isotopes; i.e. elements with common #Z" (the number of nuclear protons")#, but different numbers of neutrons, massive nuclear particles. Of course #Z# defines the identity of the element.

Even for hydrogen (#Z=1#) there are several isotopes available and routinely utilized: #""^1H#, protium; #""^2H#, deuterium;#""^3H#, trittium. For all these isotopes, #Z=1#, but there are #0,1,2# neutrons in the nucleus. The weighted average of the masses of the isotopes is the atomic mass reported on the Periodic Table.