Name and Number, Please

One advantage to on-line study is that I can do it anywhere, especially if the internet is free and the caffeine is plentiful. My over-sized laptop has traveled from the Jesuit-like austerity of the Clinton Public Library cubicles to the KC Plaza coffee shops full of selfie-taking Moms, drowsy homeless people, and nervous students. The first time I learned Chemistry I carried 3×5 index cards.  They were light and required only good handwriting and no connection, except to my memory.

This week I learned how to remember the names of compounds. The rules are almost as easy as The Name Game, but not quite as singable. The positive element goes first, followed by the negative, plus ‘ide’. HCl = Hydrogen Chloride. Ratios are identified by the Greek prefixes mono through deca. SF6 = Sulfur Hexaflouride. Suffixes vary by amount of oxygen (‘ate’ through ‘ite’) and acids end with ‘ic’.

My laptop even traveled to the Learning Forward Conference in ice-bound Dallas this week. I learned about teaching and the support that teachers need, but often do not receive, in order to grow as professionals. Overall the conference was great, even though I was disappointed to learn that the 4C’s of 21st Century Learning* do not include Chemistry.

However, in two days I was fortunate to have three elemental teachers that are gifted in three very different ways and the combination was perfect. Thanks go out to my very own poly-atomic learning compound: SkAdF2 = Sarann Difullanide. I hope to make another batch of you in my lab very soon.

Life, Death, and Chemistry

*Creativity, Communication, Collaboration, and Character

 

Castles in the Air

As with friends, families, and communities, the truly interesting behavior starts once bonding has occurred and the structure is in place. The relationship dynamic for electrons is called “Valence Shell Electron Pair Repulsion”, which is a term that will never be hashtagged ever. VSEPR means that once electrons have bonded to form pairs, they move as far apart as possible from other electron pairs. This gives rise to many different structures as the pairs jockey for space. It’s important to remember that these structures are three-dimensional even though we draw them with dots, arrows and equations.

For example, the molecule SCL4 has five electron pairs around the S atom which creates a Trigonal Bipyramid like this:

240px-Trigonal-bipyramidal-3D-balls

The molecule XeF4 has six electron pairs around the Xe atom which creates an Octahedral structure that looks a lot like the jacks that we used to play with:

th8YRUZDR0

I learned 10 structures this week, ranging from the lowly Linear, Bent, and T-Shape all the way to the magnificent Tetrahedral and Square Pyramidal. I also learned that these bonds build more than just beautiful structures. The nature of the bond has a direct effect on the physical properties of the compound. Strong bonds cause high melting points, high boiling points, and low vapor pressures. I wonder what new materials are out there waiting to be created with just the right combination of structure and strength?

Tomorrow I am travelling to attend a conference about learning. I hope to eventually build just the right classroom combination, even though right now the areas of teaching and learning seem more like alchemy – all mystery and magic – and less like the balanced and predictable study of electrons that I find so comforting.

Next Up: Name and Number, Please