9-30-13

This week we finished up our stoichiometry unit and had a test on Wednesday. Stoichiometry is the mass and amount relationships between reactants and products in a chemical reaction. After the test, we started learning about Lewis structures. Lewis structures are also known as electron dot diagrams. They are named after Gilbert N. Lewis who published his essay "The Atom and the Molecule" in 1916. Lewis structures are used to provide a simple way for chemists to represent molecules that allow reasonable predictions to be made about the structure and properties of the actual molecule. The properties of a molecule really depend on how the electrons are distributed throughout the molecule. http://www.chem.ucla.edu/harding/lewisdots.html (this website gives a description on drawing Lewis structures which really helped me as well).
Two methods the atom Ne could be drawn is

The diagram on the left shows the Lewis structure. The amount of dots surrounding the atom gives the core charge. For example, the atom Ne has a core charge of +10. 

Molecules can also be shown with a Lewis structure. Covalent bonds are shown by drawing lines. Covalent bonds are the sharing of two electrons in the valence shell of both atoms. 

 This diagram shows sulfuric acid and the covalent bonds connecting Sulfur and Oxygen and Oxygen and Hydrogen. Hydrogen must always share two electrons known as a bonding pair. Also, the sum of the shared or bonding electrons and the lone pair electrons for carbon, nitrogen, oxygen, and fluorine atoms must be eight (an octet). The other elements usually follow the octet rule as well.
This week, I'd give my understanding of our new subject about a 9. I think that I understand the topic well enough that I was able to help my classmates with questions that they had. I also think that doing this POGIL really helped my understanding, and doing the whiteboard activities and listening to other people's ideas really helped as well. I hope that I understand this unit better than the stoichiometry unit and hopefully do better on the test.