# Nitrogen has two isotopes, N-14 and N-15, with atomic masses of 14.00031 amu and 15.001 amu, respectively. What is the percent abundance of N-15?

##### 1 Answer

The percent abundance of N-15 is 0.6403%.

#### Explanation:

The atomic mass of an element is a weighted average of its isotopes in which the sum of the abundance of each isotope is equal to 1 or 100%.

**Formula for Calculating Isotope Percent Abundance **

In order to determine the percent abundance of nitrogen-15:

**Set up the formula for nitrogen-15 and nitrogen-14.**

Simplify the left-hand side.

Simplify.

Subtract

Simplify.

Divide both sides by

In case you're interested, the percent abundance of nitrogen-14 is