Unit Afterthougts

Blog Post #3

Looking back on this unit, I wish I had prepared just a bit more. I thought I knew what I was doing going into this test, but I felt panicky and had to rush to fill in answers at the last minute. I know I can do better than what I had done, but I felt as if I had pushed studying off to the last minute as well, therefore going into the test, a bit unprepared.
Current Mood: Sighing at my life, and grades.

Links I used for studying:
Molecular Geometry
Geometry of Molecules

Resonance and Geometrical Shape

Blog Post #2

In talking about resonance and geometrical structure, there were many factors that go into determining the shape. 

First off, there's bond polarity. When electrons are shared between two atoms, one atom may exert more of a force on the electron than the other one on the other atom. This pull is termed electronegativity. 

The unequal sharing of electrons within a bond leads to the formation of an electric dipole: a separation of positive and negative electric charges. 

http://images.tutorvista.com/content/electric-charges/dipole-force-non-uniform-electric-field.gif

http://i.stack.imgur.com/n7ccH.jpg

Useful Links:

Drawing Resonance Structures

Resonance

Lewis Dot Structures

Blog Post #1

Lewis Dot Structures, are diagrams that show the bonding between atoms of a molecule and the lone pairs of electrons that may exist in a molecule.

http://us.static.z-dn.net/files/d4c/abe41042ec07bc2fb42da8aac975e88a.gif

However, when making these electron dot diagrams, there are exceptions for some of the elements.
Boron is a Moron and only requires six electrons to be stable.
Beryllium only requires four electrons to be stable.
Hydrogen and Helium only need two electrons to be stable.

The Octet Rule determines how many electrons are to be placed in the valence shell. No atom can have more than 8 electrons total in their outer shell. However, the central atom can have more than eight electrons in which they call an expanded octet. 
(Elements in Period 3 and up can have expanded octets.)

We also talked about bond length and bond energy which can be summed up in this video.
Bozeman Science-Bond Length and Bond Energy

http://www.science.uwaterloo.ca/~cchieh/cact/fig/ebondh2.gif

Useful Links:
Practice Problems
A Brief Tutorial on Drawing Lewis Dot Structures.