Why am I teaching this?

Just as a preface, this post will focus a lot on my chemistry curriculum, but it applies to most courses these days.

At the beginning of every year, I give my students a Student Info Sheet to fill out.  One of the questions on there is "What 1 question do you have about Mr. Seigel?" and the most popular question every year is "Why do you love Chemistry so much?"  It is a pretty simple answer:  cool stuff happens.  I mix 2 clear liquids together and get a yellow solid; I put this metal in water, bubbles appear and it catches on fire; 2 solids are shaken in a flask and frost forms on the outside of the glass.  How could you not love chemistry?!

My love of chemistry stems from chemical reactions.  If I could have my way, that is all I would do all year:  tons of labs involving chemical reactions.  In fact, I could totally run a problem-based lab chemistry class in which we develop solubility rules, activity series, types of reactions all by doing them first and studying the results.

But then the year starts and my first units are The Periodic Table, Atomic Theory, and Bonding and Molecular Geometry.  These are three units that have few labs and are mostly notes and theoretical learning that can't be demonstrated in a HS course.  Sure there are activities that I do, but it isn't the cool stuff that happens later.

http://goo.gl/oXrla

Removing the Periodic Table from this discussion, I keep coming back to the question "Why am I teaching this?"  If I were to skip Atomic Theory and Bonding, would my students still be able to understand chemical reactions?  If you think about it, these are 2 concepts that are relatively new in the world of chemistry.  The modern theory of the atom is only about 70 years old and bonding slightly older than that.  My father gave me a chemistry textbook published in 1896 and the entire thing is chemical reactions.  No atomic theory, no bonding, no Periodic Table.  Somehow chemistry students were able to still study this subject for hundreds of years without any of this knowledge and were deemed competent in the material.  Hell, some of the greatest chemists never knew any of this.

Ignoring the fact that I have a district midterm and final that I have to prepare my students for, what would happen if I just skipped these sections?  What if my lab-based class was actually lab-based?  Am I really teaching the most important information or am I teaching it because someone else told me it was important?

So now I have asked more questions than I could possibly answer.  I would love to hear your thoughts and how you tackle these questions in your course.