Question

Find the average atomic mass x. If two isotopes of an element 35 17 x 75 percent and 37 17 x 25 percent

Answer 1

Set Abundance Equal to x

Let x equal the percentage abundance of one of the two isotopes. The other isotope must then have an abundance of 100 percent minus x percent, which you express in decimal form as (1 - x). For nitrogen, you can set x equal to the abundance of N14 and (1 - x) as the abundance of N15.