How to calculate the abundances of isotopes using algebra for students of both AS level Chemistry and A-level Chemistry.

You’ll need to use algebra to calculate the abundances of isotopes whenever you don’t know the abundance of any of the isotopes of an element. It’s actually pretty simple when you know how – but I think that this is one of those things that you really do need to be shown how to do. Even students who do A-level maths seem to struggle to find a way to approach these questions, but they’re not usually taught at school.

This lesson is made up of 4 videos, and I’m going to be asking you to do some of the work for yourself in all of them. So go grab a pen, paper and a calculator (not your phone, don’t make this harder than it needs to be).

In video 1, I’ll show you how to approach the calculations and give you some rules to follow, and we’ll revise some basic algebra. I’ll also show you an example for calculating the abundances of Boron, an element which has 2 isotopes.

In video 2, I’ll give you some more practice examples and I’ll ask you to calculate the abundances of isotopes of Chlorine and Lithium.

In video 3, it will start to get a bit more complicated as we’ll learn how to calculate the abundances for an element with more than 2 isotopes. We’ll have to make a minor tweak to the rules we learned in video 1, but we’ll look at 2 practice examples, including how to calculate the abundances of the isotopes of Magnesium.

Finally, in video 4, we’ll look at some more examples involving elements with more than 2 isotopes, but we’ll have slightly different data than we did in video 3.

By the end of the 4 videos you will be able to tackle any question that requires you to calculate the abundances of isotopes using algebra with confidence. And if you need help with anything else, contact me to arrange your introductory online lesson.

Part 1: Introduction to calculating the abundances of isotopes using algebra

Part 2: Your turn to practice

Part 3: Calculating the abundances for elements with more than 3 isotopes

Part 4: More examples of calculating the abundances for elements with more than 3 isotopes.