How matter behaves.
STRUCTURE AND BONDING
Electronic structure controls
Molecular arrangement which
the properties of matter
SHAPES OF MOLECULES
SYMMETRY IN CHEMISTRY
Beauty of form arising from balanced proportions.
The property of an object such that following specific
changes (such as moving it in space), the object
SYMMETRY AND CHEMISTR
NATURE OF BONDING
Bonding arises from the way electrons move
We usually discuss this in terms of orbitals.
The way they interact with each other while
moving through the molecule effe
MORE ON SYMMETRY
Introduction of symmetry elements and operations
Proper rotations C
Mirror planes, vertical and horizontal, v and h.
DIHEDRAL MIRROR PLANES
Tricky to distinguish from a vertica
MULTI-ELECTRON ATOMIC WAVEFUNCTIONS
AND THE ORBITAL APPROXIMATION
ORBITAL STABILITY AND ORDERING
Wavefunction for a multi-electron atom is complex
(dont get me started on molecular wave functions!)
An approximation con
MORE ON ASSIGNING POINT
SPECIAL POINT GROUPS
Linear (pretty easy to spot, not that common)
Cubic (very high symmetry, relatively easy to spot,
often very hard to identify all symmetry elements,
VAN DER WAALS FORCES
Polarizability increases with increasing volume;
larger molecules are more polarizable.
Polarizability decreases with electronegativity; atoms
which hold tight to their electrons dont let them
move around as much.
AN IMPORTANT BOND
Hydrogen bonds are weaker (~20 kJ/mol) than covalent/ionic
bonds (~400 kJ/mol), but stronger than van der Waals forces
Play a critical role in physical, chemica
SYMMETRY. WHATS IT GOOD
A molecule cannot have a dipole moment perpendicular to
a mirror plane or an axis of symmetry.
A polar molecule has a permanent electric dipole moment.
It has more electron density at one end than
We will be looking some more at
Down any group, IP decreases as Z increases
Across a period, IP increases as
First part of course looked at
Now we examine how bonds are
formed between atoms to make
Bonds arise from interactions
between electrons and nuclei.
Seems to work at all scales; one of the fundamental forces
of nature (electromagnetic force).
Look now at Coulombic interactions between atoms and
FORCE OR POTENTIAL ENERGY
Write in ter