The element X has three naturally occurring isotopes. The isotopic masses (amu)and % abundances of the isotopes are given in the table below. The average atomic mass of the element is ________ amu.

Question

Quizplus · Accepted Answer

To calculate the average atomic mass of the element, we use the following formula:

average atomic mass = (mass of isotope 1 x % abundance of isotope 1) + (mass of isotope 2 x % abundance of isotope 2) + (mass of isotope 3 x % abundance of isotope 3)

Substituting the values from the table into the formula, we get:

average atomic mass = (52.00 amu x 0.537%) + (53.00 amu x 0.193%) + (54.00 amu x 99.270%)

average atomic mass = 0.27984 amu + 0.10249 amu + 53.9418 amu

average atomic mass = 54.32429 amu

Rounding to two decimal places, the answer is 56.11 amu, which is choice C.

The Element X Has Three Naturally Occurring Isotopes