Week (Weak) of 9/30/2013

This week we covered many topics, and did a new lab in class.

The first thing we covered starting the week was bonding and bond order. When doing a Lewis Dot Diagram we represented a bonding pair with a line instead of two dots. Now we have to deal with double and triple bonds.

We went through bond order with a POGIL activity and learned that the bond order of a given molecule is the highest number of bonds it has between two atoms (which can be 1,2 or 3). We also learned that double and triple bonds have more energy stored in them, thus they are harder to form and harder to break. We then added bond length into the mix, where a higher bond length means less stored energy.

We then learned the exceptions to the rules for Lewis Structures. Boron and Beryllium are both electron deficient, with Boron only have 6 valence electrons and Beryllium only having 4. It is also worth noting that Hydrogen only has 2 valence electrons. A lot of elements are hypervalent, meaning they have more than 8 valence electrons.

We were then introduced to charges on atoms. Previously, we would put brackets around the whole molecule with the charge superscripted to denote charge. Now we can simply put the charge on the appropriate atom. We use formal charge to understand bonding better (unfortunately, it’s made my understanding worse).

Near the end of the week, we started a lab involving balloons and gumdrops about molecular geometry. Molecules can take a Linear, Bipyramidal, Trigonal, Octahedral, or Tetrahedral shape.

Friday night, we did lecture quizzes on molecular geometry and formal charges. Anything for extra credit.

This week was a good one, with a nice lab and a few new concepts thrown in. However, all these new concepts are still confusing to me, and I need to make sure I get them straightened out before the next test. I'm still bad at studying but I'll get better at it eventually.