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Re: [Phys-l] chemical bonds

These are very helpful posts. Thanks.
I have some reading to do.

Paul Lulai
Physics Teacher
St Anthony Village S.H.
3303 33rd Ave NE
St Anthony Village, MN 55418

612-706-1146
plulai@stanthony.k12.mn.us
http://www.stanthony.k12.mn.us/hsscience/ ;

-----Original Message-----
From: phys-l-bounces@carnot.physics.buffalo.edu [mailto:phys-l-bounces@carnot.physics.buffalo.edu] On Behalf Of John Denker
Sent: Wednesday, December 15, 2010 11:02 PM
To: Forum for Physics Educators
Subject: [Phys-l] chemical bonds

On 12/15/2010 09:24 PM, LaMontagne, Bob wrote:
Field lines come from and terminate on charges. What are the source
particles for "bonds"? Is there a difference between these stretchy
bonds and plain old electric fields?

The bond energy is partly the plain old electrostatic energy, but
also partly kinetic energy.

The kinetic energy contribution is not to be trifled with. Many
of the most basic, crucial things we know about atomic / molecular
physics (aka chemistry) could not possibly be explained by electric
fields alone. These include:
a) the fact that atoms have any nonzero size;
b) the fact that some bonds are directional;
c) etc. etc. etc.

Coulomb's law is spherically symmetric, so it could never explain
a directional bond. The nontrivial shape of everything from water
molecules to DNA molecules depends on having some directionality
to the bonds.
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