I recently stumbled across a blog about the use of BCA (Before Change After) tables for stoichiometry written by Lowell Thomson. I was thrilled to discover ChemEd Xchange! I wanted to share my journey, spurred on by my students, into the extensive use of the BCA approach in AP and
For my students and me, the AP Chemistry exam does not mark the end of the school year. Once the AP exam is over, my students are exhausted but our class continues to meet for three more weeks. Each year we complete a qualitative analysis lab, but this year we finished earlier than I anticipated. For the first time all year, I have the luxury of time.
I am facing what many teachers are facing. It is AP week, I am trying to continue "as usual" with doing labs and learning but this time of year is anything but "as usual". There is a rates lab we do this time of year which is a good lab, rather involved with a significant amount of set up and work. I got an idea for a slightly different rates lab from Bob Worley. I found a similar large scale version from Flinn Scientific. Thanks to Bob, I decided to do a microscale version.
We’ve all seen and use the so-called Aufbau Diagram. It is a mnemonic used to remember the order of “filling” of atomic orbitals during the construction of the ground state electron configurations of the elements. The presentation of this diagram is largely disconnected from any physical meaning. Here’s what we tell our students: “Memorize the diagram, learn to use it, and you’re guaranteed to get the right answer.”
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.
In one of my last blog posts I wrote of how I sometimes enjoy ending a unit with a series of demonstrations and using them to elicit a dialog between the students and myself to check for understanding. It is always a fascinating experience to hear the misconceptions that many students have the day before the test.
In this blog post I'll describe a recent attempt at using BCA Tables for teaching stoichiometry. I discuss the method I used with one introductory chemistry class to teach both the algorithm method and BCA tables to learn more about a technique I've been curious about for a while.
A simple multi-faceted lab activity for the first week of AP Chemistry.
Lauren Stewart discusses why she is having her students build 3-D models BEFORE teaching them to draw Lewis structures.
While attending a professional development session last year I was introduced to the Talk Science Primer, developed by the Inquiry Project and TERC. Although the research and sample population targeted educators and students grades three through five, I decided to review the material to analyze if it had any value in a chemistry classroom.
