Ball-And-Stick “Lab”(Really just an activity, not a true lab, but it goes into your lab grade because it’s cooperative and

involves manipulating something three-dimensional, not just the usual pencil & paper)

Ppt init 10/22/2014 by Daniel R. Barnes based on a lab I’d been doing for years.

NOTE: As with all my presentations, this one may contain images and other intellectual property that was stolen from the Internet without permission of the owners. Do not copy, distribute, or store this presentation. It is meant to be viewed only by Mr. Barnes’ students, and then only during the year that they have him as a teacher. The very existence of this presentation may be illegal. I’m not a lawyer, so I’m not sure. I just know there’s a job I gotta do, with urgency.

hydrogen 30 pm small Very common atom 1

carbon 77 pm med Coal, charcoal, soot 4

oxygen 66 pm med Blood, rust, fire 6

nitrogen 70 pm med Air/sky 5

SOME RULES:1. Take turns being the one with the materials (whiteboard, dry erase marker, balls, and toothpicks). New chemical, new person.

2. Only the person whose turn it is can touch the materials.

3. Everyone else is encouraged to communicate ideas to that person, but remember that only the person who is “up” can actually touch the materials.

4. No benchwarmers. No ballhogs.

5. Leave the cap on the pen and don’t doodle with it.

The valence shells in both methane and water have a tetrahedral shape, but the name of a molecular shape is chosen based solely on the positions of the atoms, not including non-bonding valence shell electron pairs. Therefore, water is considered to be “bent triatomic” rather than tetrahedral. Secretly, the tetrahedron is hiding in there.

http://www.scienceforums.net/topic/67272-when-water-can-form-an-h30-ion-why-cant-it-form-an-h4o2-ion/

If you pop some hydrogens on the ends of those non-bonding pair toothpicks, you can turn H2O into H3O+ or, maybe H4O2+, but there are controversies about the existence of those two species, especially the latter. The link below takes you to a spirited, almost rude argument about these species. It’s so technical it’s probably good for chem teachers only.

H H CH

H

H

H NH

H

H O

H

H

CO O CH

H

H

C

H

H

H CH

HC

H

H

CH C H CH

H

H

C

H

H

HC

H

H

CH

HO