After spending the start of the year using a modified version of the Modeling Instruction curriculum (density and physical properties, followed by gas laws, followed by energy and phase changes), we don’t actually start talking about what’s inside atoms until December. I love that by this point students are already familiar with some of the habits of mind needed to reason abstractly about atoms -- thinking proportionally, explaining macroscopic observations at the particle level -- and we are ready to layer on both more abstraction and the symbolic level. By January, we are ready to explore electron configurations.
Most chemistry teachers I know do flame tests with their students. It ties in well with many topics, is colorful and the kids enjoy seeing the colors and burning stuff. There are many applications. For years I always mentioned that astronomers use the idea of the flame test. They simply look at stars and examine the spectra from the light of these stars. They then match the spectra with the elements and then they can see and infer what elements are millions of light years away. I always mentioned this but never was able to demonstrate it.
After receiving positive feedback from Peter Mahaffy, the IUPAC project co-chair of Isotopes Matter, I decided to add an additional component to the original isotope assignment I posted. The second component of the assignment focuses on the applications of both radioactive and stable isotopes using the interactive IUPAC periodic table.
A complete understanding of why each element has a particular electronic configurations is a very complex subject. Even so, some confusion regarding the electronic configurations of the elements may be alleviated by looking at the physical properties of the electronic orbitals.
Have you ever wondered what is the theoretically largest possible value for the atomic number of an element? Using some introductory physics and algebra, you can get your students thinking about this idea.
Are kids learning? Given the time it takes to implement and grade the activity, do I get a lot of "educational moments" out of it? Does it fit into the culture of the classroom? Is there a great deal of "conceptually rich" material in the activity that students can build on? I believe that two activities I tried this week fit the bill.
Last year while attending the Biennial Conference on Chemical Education at GVSU I had the opportunity to hear a talk that showed a video of a chemical demonstration showing the burning of magnesium metal. We have all seen many of these videos (thank you YouTube) and probably have performed this demo for our own students many times. During the video it may have been represented with a chemical equation followed by the students being asked to balance the equation or maybe even predict the products. Although the use of video including the showing of the equation nicely represents the macroscopic and symbolic representation, what was so unique about this particular video is that it also included the particulate representation embedded on top of the video of the demo. This was the first time I had seen the particulate level representation done like that and so I was intrigued in wanting to find more of these representations.
In this Activity, students investigate the luminescent properties of common items such as glow-in-the-dark stickers, wintergreen-flavored hard candies, and a chlorophyll solution made from spinach leaves. After making observations, they use a flowchart to categorize the luminescent items as fluorescent, phosphorescent, or triboluminescent.
Orbital Viewer is a fantastic program for displaying electronic orbitals. It is a great resource for teaching students about orbital shapes and the rules, nomenclature and notation of the quantum numbers n, l and m.