Q. 4.41 - An Introduction to General, Organic, and Biological Chemistry

Question

Copper consists of two isotopes, ${}_{29}{}^{63}Cu$ and ${}_{29}{}^{65}Cu$.If the atomic

mass for copper on the periodic table is $63.55$, are there more

atoms of ${}_{29}{}^{63}Cu$ and ${}_{29}{}^{65}Cu$ in a sample of copper?

Step-by-Step Solution

Answer

There are more atoms of ${}_{29}{}^{63}Cu$ in a sample of copper.

Step 1: Given Information

We are required to determine which copper isotope is more naturally occurring in nature. Here, we are given the atomic number and the atomic masses of the two isotopes of copper and we also have the average atomic mass of copper.

Step 2: Explanation

We know that

The atomic mass of an element on the periodic table is used to find the most abundant isotope. The atomic mass of copper is $63.55 amu$, as can be shown. Although no copper atom has that mass, it is the average mass of a copper sample.

When comparing the atomic masses of ${}_{29}{}^{63}Cu$ and ${}_{29}{}^{65}Cu$ , we can see that the atomic mass number on the periodic table is closer to that of ${}_{29}{}^{63}Cu$.

We can deduce that ${}_{29}{}^{63}Cu$ is more plentiful.