Section B Flashcards
How does Hybridisation effect Spin pairing and Spin exchange energy
you will Lose the spin pair energy but
you Gain spin exchange energy
MO Theory - 3 Rules
- A molecular orbital is full when it contains two electrons with opposite spin (Pauli Exclusion Principle)
- Molecular orbitals of lower energy are filled first (Aufbau principle)
- Where molecular orbitals are of the same energy (degenerate), electrons will aim to minimize repulsion by singly occupying the orbitals with parallel spins (Hunds rule)
Rule of combining orbitals
The number of orbitals are always conserved.
If you combine two atomic orbitals you will always form two molecular orbitals.
Wavefunctions
Lect 6
Pictures of Phase mixing
Bond order =
2
Does not have to be Integers *
How does an antibonding orbital effect a molecule?
It’s presence weakens the bonding interactions
HOMO
Highest occupied Molecular Orbital
Diagram
LUMO
Lowest occupied Molecular Orbital
Diagram
How is HOMO and LUMO relevant?
Electrons can be lost from the HOMO
and Gained in the LUMO
Must Learn MO for B2, C2,N2 and H2
Diagrams
Paramagnetic
def
Unpaired electrons
O2
He
Diamagnetic
def
Paired electrons
H2
MO diagram for HF
Diagram - Explain how it works
Isoelectronic
def
two atoms, ions or molecules that have the same electronic structure and same number of valence electrons.
- Same Electron Config !!!
The K+ ion is isoelectronic with the Ca2+ ion. The carbon monoxide molecule (CO) is isoelectronic to nitrogen gas (N2).
Isoelectronic
def
two atoms, ions or molecules that have the same electronic structure and same number of valence electrons.
- Same Electron Config !!!
The K+ ion is isoelectronic with the Ca2+ ion. The carbon monoxide molecule (CO) is isoelectronic to nitrogen gas (N2).
