Embedded Files
Unit 1 TESTS will be the first week in October. Review materials are available HERE already. Start studying!
Video 1: What are Isotopes and Calculating Average Atomic Mass
Video 2: Calculating Percent Abundance From Average Atomic Masses
Other Content Videos
Other Content Videos
Open the menu below for other vids by other teachers. These videos are NOT required, but do offer a different perspective on the topic if that helps!
Tyler DeWitt - A different take from one of the most famous YouTube chem teachers. I've seen this guy do Ted Talks! He includes a great analogy for better understanding what isotopes are.
chemistNATE - An example on how to calc average atomic mass
chemistNATE - Another example of calculating average atomic mass
Written Content
Written Content
Open the menu below for typed content, like in a textbook. Some prefer to learn from reading rather than watching. If that helps you these resources can be useful!
CK-12 - Very brief runthrough of the definition and how to do the math. Lots of examples included!
American Association of Chemistry Teachers - This site has a set of practice problems that allow you to make your own set of isotopes for a mystery element like chemistrium, to calculate a unique average atomic mass. Make up your isotopes, make up some percent abundances, and it creates a practice problem for you to try and check your answer. Fun!
Average Atomic Mass Calculator - This site hosted by the ACS provides a visual tool to show how average atomic weight is calculated for each element on the periodic table. Also show the full setup for the calcs.
Resources
Resources
The data or tables below are REQUIRED to be able to do the work in this section. Make sure you have access to these when needed OR download/print your own copies!
Table of Isotopic Abundances - Tons of sig digs in the data and ALL isotopes for ALL elements. The trade off is this table is MANY pages long! This data will get you results that match the periodic table almost perfectly! Use this table to calculate the average atomic masses of any element.
Class Practice
Using the Table of Isotopic Abundances linked above, calculate the following information:
Choose any 10 elements and calculate their AVERAGE ATOMIC MASSES
It must be 10 DIFFERENT elements
Only 2 elements can have the same number of isotopes. For example, if you choose to work with potassium (3 isotopes) then only one other element you choose can have three isotopes. The rest must have more of fewer isotopes. This is make sure you choose a variety of different elements with different difficulties.
Explain why your answers are different from the ones on the periodic table. Use the concept of significant digits to help in your explanation.
Use the Average Atomic Mass data from your Periodic Table and calculate the % abundances from any 3 elements on you Table of Isotopic Abundances that have ONLY 2 ISOTOPES. Chlorine is an example of an element with only 2 stable isotopes, but there are many more.
If you are clever and want to make this work easier, do it all in a spreadsheet! This will help to organize your work AND the spreadsheet can do a lot of this math for you. Ask me how!
This is a virtual lab activity using a website created by the University of Colorado called PhET. Their simulators are very popular in chemistry and physics classrooms since they make for great examples of experiments that can be hard to do in a HS classroom.
The link above will bring you to a doc with instructions on how to access the simulator as well as what to do and what data to collect.
Mastery Quiz
Mastery Quiz
To prove mastery of this topic you will need to take a quiz on Schoology. Here are the guidelines:
You must show me all the completed work for this section BEFORE you you can start attempts on this quiz.
You can use any notes, practice, or prior quiz attempts to help you complete the quiz.
You can use ANY class resources like a calculator, your periodic table, or any other reference materials
You have UNLIMITED attempts to take this quiz, but after 4 tries you will need to take a paper version with me in class.
You should only need 2-3 tries for each quiz. If it takes more than that you should be reaching out for help!
You CANNOT work with others on the quizzes
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