I've Lost Count of How Many Weeks it's Been

I cannot speak very heavily on any subject in particular regarding this week; it was a mixed bag of varied things. I guess I should give a day-by-day account of what we did.
On Monday, we did a lot of test review on molecular shapes, Lewis structures, VSEPR and the like. I think that the stuff that I was most worried about, I ended up understanding better than the stuff I felt like I had down pat. Alas, I must learn to review more effectively.
On Tuesday, we took the test. I was able to finish it all this time! I felt really good about my short response and solid on multiple choice. These turned out to be pretty accurate when reflected in my grade. Overall, I really liked this unit.
Wednesday:

(Yes, that's a mole cookie.)

And that pretty much sums up Wednesday.

Oh, and we also wrote essays on polarity that had to do with paintballs. This wasn't very hard in my opinion, but it was really kind of vague. Also, seeing as none of us had written an essay in a science class, it was pretty awkward. But anyways, here is my essay if you have any interest in paintball chemistry.

Thursday, we took a practice AP exam (multiple choice). I actually apparently scored rather well. Obviously there was a lot of stuff I didn't know, but I'm kind of excited to learn the rest of it in the upcoming months.

On Friday, we started learning things again. We did some POGILs on metals and ionic bonds. Basic difference between ionic bonds and covalent bonds: covalent bonds involve the sharing of electrons between two atoms, whereas ionic bonds are when one of the two atoms sacrifices one of its electrons and gives it to the other. Metals, as they form cations, usually form ionic bonds with anions and if there are two nonmetals, they usually form a covalent bond. 

That's all for this very exciting/bizarre week!

(Also I have another mole day joke.

What did Avogadro yell at the Battle of San Jacinto?

Remember the Alamole!)

Week 5: Pumpkins and Mozart

Soundtrack for the week!

Here's a thought: Why isn't VSEPR pronounced vuh-seh-pur instead?

We kicked off the week by making more models. But instead of making electron-domain balloon models like this...

We made toothpick and gumdrop models like this. 

This was the second half of the VSEPR packet that we did. These models show the molecular geometry, which usually looks different from the electron domain geometry. They look so different because the balloon models show where each electron is likely (LIKELY) to be at any given moment. The gumdrop models show more the angles at which each atom is bonded to the central atom. The central atom isn't visible in the electron domain geometry, but it is visible in molecular geometry. The biggest difference is that molecular geometry models only physically show the electrons that exist in bonds, while electron domain geometry models also show nonbonded valence electrons. The point of this exercise was to make us have to actively think and work on how these models work with each other, rather than only having us do the lectures (which can get hypnotic and bland at times). As Dr. Finnan seems to think, others' failure is an excellent way to learn. Which is true.
In my understanding, the main idea of VSEPR is that the electrons and protons within each molecule naturally repel each other and attract each other. This makes them settle into certain shapes to be the least repellent and volatile. Kind of how the balloons settle to have the least friction.
Other things we did this week:

• Formal charges. Formula for calculating formal charge: FC = V - N - (B/2). You put the formal charge in the Lewis structure, then add them all up for the molecule. You always want the structure with the lowest charges, because it's more correct. 
• Hypervalency (and electron deficiency). Hypervalency is when a central atom holds more than eight valence electrons. This can only happen in periods 3-7 on the periodic table. 
  
  Phosphorus pentachloride, pictured above, is a prime example. Boron and beryllium may be electron deficient, given their number of orbitals. 
  
  
  Weekly chemistry joke: Helium walks into a bar and orders a drink. The bartender curses and yells "We don't serve noble gases here!"
  Helium doesn't react.
  Ba-dum-chhhh. 
  
  

Week 4: I learned how to tie a balloon!

This week has been my favorite week so far. We've learned a good deal through a variety of activities. We did quite a few POGILs, a lab, and some modeling activities.
The lab this week was dealing with the concentration of copper in a solution and how it relates to absorbency. I was unfortunately absent for Wednesday and missed the fun reactions (and truthfully I'm still a little confused as to what's going on). But the group that I'm in did the correlation curve instead of the visual, which I enjoy doing because I think colorimeters are fun. This lab is kind of similar to our first lab.
Labs make this class so much better. I often sit in math class and think to myself, why am I learning this when I know I'll never use it in real life? I think that if we did no labs and just did POGILs and worksheets all year this class would take on a similar effect. Thankfully, we do other things which makes this a rather lively course.
We also started an activity where we made balloons into molecules in order to better visualize what they actually look like. This involves blowing up and twisting together red and white balloons (symbolizing electron clouds). This is a really good way of teaching us materials, as we're more excited about participating and we have to understand the concept in order to finish it. We haven't yet finished this activity, but I believe we're also going to make models out of toothpicks and gumdrops. I think the purpose of this activity is to get us to understand that Lewis models, despite their undebatable usefulness, aren't actually visually accurate. I imagine that this might have been a common misconception. I was searching the internet for "balloon molecules" and I found a very different approach to making balloon models using long balloons. This seems like a cool idea.

On the homework front, we've been doing tons of lecture quizzes, which I enjoy. I usually watch them all twice, so I can get a better idea of the whole picture instead of little chunks only. I also like that the questions make me think about the concepts rather than just doing work.
For your weekly science meme, Chemistry Cat is back!