Question

The term “ average atomic mass “ is a ______average so is calculator different Lee from a normal average

Answer 1

Average atomic mass of an element is a sum of the product of the isotope mass and its relative abundance.

For example: Chlorine has 2 isotopes with the following abundances

Cl(35): Atomic mass = 34.9688 amu; Abundance = 75.78%

Cl(37): Atomic mass = 36.9659 amu; Abundance = 24.22 %

Average atomic mass of Cl = 34.9688(0.7578) + 36.9659(0.2422) =

                                             = 26.4993 + 8.9531 = 35.4524 amu

Thus, the term “ average atomic mass “ is a weighted average so it is calculated differently from a normal average