The cracks in the table... that's how the light gets in.

Recalling my first experience with the periodic table, reading my mother's high school chemistry texts, it seemed to me that the periodic table was a kind of "work of reference," a handy list of the elements, ordered into peculiar palisade of columns. It served mostly as a kind of arcane crossword puzzle.

So light bulbs are full of argon... where is argon on the periodic table?

or...

There really is a Krypton! The Superman comics are so cool!

To me, the structure of the table remained an exercise in authority, unquestionable as a stop sign.

Mr. Slavin was the first to take a hammer to the table. Mr. Slavin was my grade 9 electronics teacher, an inventor himself, who taught us the basic Bohr quantum description of the atom so that he could explain to us how semiconductors worked. In a few weeks, we were able to describe silicon doping, the structure and function of P-N diode junctions, N-P-N transistors, and amplifier circuits. Man... try that in Toronto today!

The light slowly began to appear through the first cracks in the odd ranks of elements. Mr. Slavin's vocabulary allowed some of us kids to begin to see patterns in valence shells of the Bohr atoms, related to columns of the table.

In my experience, that is precisely the place where most of my students began to perceive the structure underlying the periodic table. Check out the table in the header of the blog. You can see the familiar Bohr valence structure of the main block elements. But where are the rest of the details of the Bohr atom? You can find a discussion of that here. I'll continue here tomorrow.