Transcript lecture01-2004.ppt

Today’s Goal:
Start thinking about
how molecules exist
and interact in a
condensed state
Two Types of Atomic
Interaction:
Covalent Bonds
(make molecules)
Non-covalent Bonds
(make molecules come alive)
BOND PREFERENCES
Hydrogen:
Oxygen:
Nitrogen:
Carbon:
1
2
3
4
covalent
covalent
covalent
covalent
bond
bonds
bonds
bonds
Two Types of Covalent
Bond:
Non-polar
(electronically balanced)
Polar
(electronically unbalanced)
Molecules “see” each
other by non-covalent
interactions of their
electron shells.
4 Types of
Non-covalent Bonds:
(1) van der Waals
(2) hydrogen bonds
(3) ionic
(4) hydrophobic effect
QuickTime™ and a
decompressor
are needed to see this picture.
4 Types of
Non-covalent Bonds:
(1) van der Waals
(2) hydrogen bonds
(3) ionic
(4) hydrophobic effect
Covalent and non-covalent
Chemical bonds:
Bond type
Covalent
Non-covalent: ionic
hydrogen
van der Waals
length (nm)
0.15
0.25
0.30
0.35
strength (kcal/mole)
in vacuum
in water
90
90
80
3
4
1
0.1
0.1
Next Class (2/10):
“Molecular
Workbenches”
Protein structure
&
function