A.P. Chemistry – Snow Days Refresh!

Hi Guys!

We have missed a total of 6 school days in the last 2 weeks, 5 snow days and one day I was out. In order to refresh your brains about this unit, you need to watch these videos and add to the notes I have already given you. Please have this completed by Monday, 3/9. There are quite a few videos (27) so PLEASE do NOT wait until the Sunday before to start watching them, I will be checking up on your progress every two days. You should be watching 3 videos a day, they are not long, usually about 10 minutes each.

https://www.khanacademy.org/science/chemistry

Click on “Electronic Structure of Atoms”
Watch the videos under Bohr’s Model of the Atom and Electron Configurations

Click on “Periodic Table”
Watch the videos on the Periodic Table Trends.

H Chemistry – Covalent Molecules & Lewis Structures

Here are the steps for writing Lewis Structures for Covalent Molecules.

1. Add up the total # of valence electrons from all atoms in the compound.
2. Divide by 2 to determine the # pairs of electrons available to bond.
3. Determine the center atom, it’s always the element with the lowest electronegativity (closest to the left side of the Periodic Table). All the other atoms in the compound are end atoms. EXCEPTION, hydrogen is NEVER a center atom.
4. Draw the molecule, place a line, which symbolizes a bonded or shared pair of electrons between the center atom and each end atom.
5. Determine the # lone pairs of electrons left (only attached to one atom, not shared) by subtracting the # of lines you just dew (shared pairs of electrons) from the # pairs of electrons available to bond.
6. Starting with the end atoms, place the lone pairs (as 2 dots) around each end atom so that each one has a total of 4 pairs of electrons around it (lines + dots). This will satisfy the octet rule. If you have lone pairs left over after doing the end atoms, then place the remaining ones around the center atom.
7. If you run out of lone pairs before the center atom has 4 pairs, you will have to erase a lone pair or two from an end atom and make a double or triple bonded pair (two lines or three lines) between that end atom and the center atom.

Here is a video with some examples. They skip step 2 but the idea works out the same.

H Chemistry – Announcements

o Parent Power Presentation – March 3 at 6:30 in the Media Center
o Parents of 9th, 10th and 11th graders – Plan to attend the “College Credit Now” Summit on Thursday, March 12th from 6:00 to 8:00 pm at Campbell High School. Meet college representatives from Georgia State University, Georgia Highlands, Georgia Perimeter and Chattahoochee Technical College as well as representatives from the DOE. LEARN ABOUT 100% PAID TUITION AND EARNING COLLEGE CREDIT WHILE IN HIGH SCHOOL.