Monday, October 18, 2010

preparing to teach the structure of the atom....

I'm preparing to meet with some students at SDSU who are enrolled in chem 200. I taught the lab for this class back in 2000-2002 so I'm familiar with the textbook and general setup of the class. Actually, I'm using the old text I used as a TA! They are now on the 5th or 6th edition of the book and I'm using the 2nd. (Hint for those of you wondering if you need to buy the next edition every time it comes out)

The concepts I'm preparing for my 200 students are very similar to those I'm preparing for my chem 3 students up in Irvine. We're beginning our study of atomic structure mostly focused around how electrons move in orbitals around the nucleus of an atom. It is these trends that determine most of the trends in how elements behave on the periodic table. If a student understands electronic structure, that student will make more accurate predictions about chemical behavior of different elements.

The first step to really understanding atomic structure is to realize that nothing that is observed in intuitive. To that end I would like to describe the study of atomic structure less as "understanding" and more as "acceptance" about what is observed by experiment. It is too bad we cannot invest in laboratory equipment to demonstrate atomic structure by experiment to all students. Unfortunately, the cost and convenience of doing such is entirely unrealistic and we must resort to explaining what scientists observe when they run these types of experiments. After reading several different ways that atomic structure affects trends in the PT, students will begin to see patterns, learn vocabulary and grow to accept experimental observations. Ideally, they will be able to use this acceptance (rather than "understanding") to make educated guesses about how other trends might function.

But- it's all tied into an understanding of electromagnetic radiation as well. The energy of electrons and how energy is distributed in chemical reactions is done through electromagnetic radiation. This is why there is an entire section about how our understanding of light and energy has changed over the years.

This is a fascinating subject to learn but I must admit, there is a certain amount of drilling and memorization that must accompany your first attempt to learn it. You will encounter concepts, observations and ideas that are completely foreign to you. I recommend whipping out those flashcards that you used to learn the polyatomic ions and using them to drill yourself about the basics of atomic structure.