Atomic and Molecular forces

Class content > Energy: The Quantity of Motion  

 

Prerequisites

 

• Charge and the structure of matter
• Polarization
• Electric potential energy

 

While chemical bonds and chemical reactions are critical for the functioning of an organism, the longer range interaction forces between atoms and molecules also play a huge role in biology. For example, it is well known in biology that the shape of a molecule determines how it functions. A genetic change that changes a molecule's shape can change its function dramatically.  A significant part of this is the electrical attraction between molecules. Let's consider a few questions about the interaction of molecules.

 

• If atoms are electrically neutral (with an equal number of protons and electrons in each atom), what makes them stick together to form molecules and larger structures?
•  Conversely, if something makes atoms attract each other, what makes them stay some distance apart, instead of moving all the way together?  Why don't molecules (and everything made of molecules) implode?
• How can we model this interaction quantitatively?
• And what does all of this have to do with energy?

 

For the answers, read the follow-on pages on Interatomic forces, Molecular bonding, and Hydrogen bonding.

 

Follow-ons:

• Interatomic forces
• Chemical bonding
• Hydrogen bonding

 

Ben Dreyfus and Joe Redish 11/15/11