Using IUPAC's Isotopes Matter as a Digital Learning Tool

Isotopes Matter

The first unit of chemistry, no matter your content sequence, is an opportunity to use formative assessments to identify student prior knowledge. In addition, this is also a time for your students to get an idea of your instructional approach and how they will be participating in class. For many chemistry teachers, the structure of the atom is the initial unit that serves not only as a review for many topics but a manner to address misconceptions and gaps in student content knowledge. A resource that I have found useful to not only assess the content understanding of the students but their peer to peer discussion etiquette is the resource Isotopes Matter.

Isotopes Matter is a digital learning tool, developed by IUPAC Isotopic Periodic Table, designed to explain isotopes as well as their importance. This resource incorporates mass spectroscopy data into each of the key ideas as well as provides multiple examples as to how varying isotopes are commonly used.

The activity I have developed is assigned during the first week of school to not only review the content but to identify baseline levels for scientific explanation as well as student-led discussion.   

In the first part of the lesson, I provide the students with a claim in which they have to explain using the Isotopes Matter resource as their content guide. Even though I provide the students with the website, it is their responsibility to determine the essential information in order to support the claim. In the second part of the activity, students choose an example in which isotopes are useful in the real world. After the students have completed both parts of the assignment the next component is to communicate their key ideas to their small group as well as the entire class. Students in their small groups can use a whiteboard to organize their thoughts or explain the key ideas their group found about each section to the rest of the class.

 I do expect students to be confused on what they should say during the discussion however they do have a small group of students that they can ask. Although multiple groups may have similar information that they identify, the discussion is important because the students practice informal presentations, as well as identifying information that they agree, is important to answering the learning target.

After reviewing my activity, if you have any suggestions to improve the assignment while maintaining the overall goals please share in the comments section below.

You will find the student document in the Supporting Information below (sign into your ChemEd X account to access).

Editor's Note: Extension Activity with Isotopes Matter is an excellent follow up to this activity.


mass spectrometer

Learning Targets:

  • I CAN identify isotopes and explain their uses
  • I CAN interpret mass spectrometer data to determine the mass of an unknown sample.
Procedure time: 
50 minutes
Time required: 

Using Isotopes Matter and the class discussion: 55-60 minutes



- 10th-12th graders who have completed a physical science class 



 - Students have used the Claim-Evidence-Reasoning (CER) template for scientific explanation in previous classes

 - Students have participated in peer to peer discussions and positive classroom environment activites in the days leading up to this assignment 


What is an Isotope? Part One Directions:

Using the web-based simulation, Isotopes Matter, explain the claim that is listed below. Because the claim is already provided, your job is to identify evidence from the simulation and justify why it is important to support the claim. If you are unfamiliar with the Claim-Evidence-Reasoning format, please refer to the CER resource before you begin.  The manner in which you organize your information is up to you however be prepared to share it with your small group as well as the class.


Claim: Atoms that have the same number of protons may not have the same mass.



Why Should We Care? Part Two Directions:

Under the Key Ideas tab, click on Idea 6: Otzi the Iceman. This section discusses why isotopes are useful in various manners. At the end of this section you will reach a page titled, Why Should We Care, open the Isotope Ratio Mass Spectrometry Learning Tool and click on one of the examples in which isotopes can be useful. The manner in which you organize your information is up to you however be prepared to share why isotopes are useful with your small group as well as the class.



Students will need:

  - computer with Internet access 
  - computers must be able to support JavaScript
  - whiteboards & dry-erase markers (optional) 


Isotopes Matter is a project developed by IUPAC


Students that demonstrate understanding can develop models to illustrate the changes in the composition of the nucleus of the atom and the energy released during the processes of fission, fusion, and radioactive decay.

*More information about all DCI for HS-PS1 can be found at and further resources at


Students that demonstrate understanding can develop models to illustrate the changes in the composition of the nucleus of the atom and the energy released during the processes of fission, fusion, and radioactive decay.

Assessment Boundary:

Assessment does not include quantitative calculation of energy released. Assessment is limited to alpha, beta, and gamma radioactive decays.


Emphasis is on simple qualitative models, such as pictures or diagrams, and on the scale of energy released in nuclear processes relative to other kinds of transformations.

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Comments 4

Deanna Cullen's picture
Deanna Cullen | Mon, 09/12/2016 - 11:13

Hi Michelle! I tried this out with my AP students today. Much of the material was review for them, but I was excited to have them see the mass spec data provided by! This excercise gives them an opportunity to explore the evidence we have for the existence isotopes. I think that next year, I will just give students the website as a reference when they are reviewing. I hope to pull together a worksheet of related questions to guide them through a review. Maybe a good essay question requiring claims, evidence & reasoning.

I am looking forward to making this a part of my regular chemistry curriculum as we move forward. I am wondering if you can provide the CER resource (or link to it) that you mention in the handout?

Thanks for sharing about! I am anxious to explore the resource even more.


Michelle Okroy's picture
Michelle Okroy | Sun, 09/18/2016 - 21:47

Hi Deanna,

    The CER resource was developed by IQWST, Investigating and Questioning our World through Science and Technology. Although the model targets middle school students I believe it is useful for chemistry students at the beginning of the year as we reintroduce justification.


Peter Mahaffy's picture
Peter Mahaffy | Tue, 09/13/2016 - 21:56


As the IUPAC project co-chair, I'm delighted to see that you're introducing isotopesmatter to your students!  The resource was intended to get at nature of scientific evidence issues, and you're making good use of the applets, such as the mass spectrometer and the atomic weight calculator.  I'd be interested in knowing if your students are surprised by or particularly interested in any of the applications of isotopes that they find when they click on elements on the interactive periodic table. When talking about isotopes, radioisotopes get a lot of attention, but the stable isotopes, also, have fascinating applications.

Best wishes,


Michelle Okroy's picture
Michelle Okroy | Sun, 09/18/2016 - 21:56

Hi Peter,

     Thank you for taking time to review my activity. I am so glad you mentioned the applications of isotopes because that is the next component of this assignment. Although not yet developed I will be sure to add applications of stable isotopes as well. Stay tuned for another activity post. 

Thanks again for the feedback.