Chapter 4.3, Problem 32LC

Interpretation Introduction

Interpretation : It is to be explained why the atomic masses of elements are generally not whole numbers.

Concept Introduction : The weighted average mass of the atoms in a naturally occurring sample of an element is the atomic mass.

Answer to Problem 32LC

The atomic masses of elements are generally not whole numbers because the atomic mass value depends on the isotope mass and relative abundance which might not be a whole number.

Explanation of Solution

The weighted average mass of the atoms in a naturally occurring sample of an element is the atomic mass.

The mass and relative abundance of isotopes as they appear in nature are both reflected in the weighted average mass.

The weighted average of all an element's isotopes' masses is used to determine an element's atomic mass. The foundation rests on relative abundance.

For the calculation of atomic mass, multiply each isotope's mass by its natural abundance, represented as a decimal, and add on the products.

The atomic masses of elements are generally not whole numbers because the atomic mass value depends on the isotope mass and relative abundance which might not be a whole number.