A sample of an element consists of two isotopes.The percent abundance of one of the isotopes is 75.0%.What is the percent abundance of the other isotope?
A) 62.5%
B) 37.5%
C) 12.5%
D) 75.0%
E) 25.0%

Question

Quizplus · Accepted Answer

The percent abundances of all isotopes of an element must sum to 100%. If one isotope has a percent abundance of 75.0%, the other must have a percent abundance of 100% - 75% = 25.0%.

A Sample of an Element Consists of Two Isotopes