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32 Cards in this Set
- Front
- Back
2 electron groups, occupy positions opposite the central atom
bond angle? |
linear geometry
180 |
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3 electron groups
bond angle? |
trigonal planar
120 |
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4 electron groups
bond angle? |
tetrahedral
109.5 |
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5 electron groups geometry?
positions above and below the central atom are called? positions in the same base plane as the central atom are called? bond angle between equatorial positions? bond angle between axial positions? |
trigonal bipyramidal
axial positions equatorial positions 120 90 |
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6 electron groups
bond angle |
octahedral
90 |
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3 electron groups, 1 is a lone pair
bond angle? |
trigonal planar-bent
angle < 120 |
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4 electron groups, 1 is a lone pair
bond angle? |
pyramidal
angle < 109.5 |
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4 electron groups, 2 are lone pairs
bond angle? |
tetrahedral-bent
angle < 109.5 |
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5 electron groups, 1 is a lone pair
angle between equatorial positions? angle between axial and equatorial positions? |
see-saw
<120 <90 |
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5 electron groups, 2 are lone pairs
angle between equatorial positions? angle between axial and equatorial positions? |
T-shaped
<120 <90 |
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5 electron groups, 3 are lone pairs
angle between equatorial positions? angle between axial and equatorial positions? |
linear shaped
<120 <90 |
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6 electron groups, 1 is a lone pair
angles between axial and equatorial positions? |
square pyramid
<90 |
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6 electron groups, 2 are lone pairs
angles between equatorial positions? |
square planar
90 |
|
hybridization
3 electron groups? |
trigonal planar
sp2 |
|
hybridization
4 electron groups? |
tetrahedral
sp3 |
|
hybridization
5 electron groups? |
trigonal bipyramidal
sp3d |
|
hybridization
6 electron groups? |
octahedral
sp3d2 |
|
hybridization
5 electron groups in period 3? |
trigonal bipyramidal
3sp3d |
|
hybridization
6 electron groups in period 5? |
octahedral
5sp3d2 |
|
Molecular Orbital Energy Diagrams
Groups 3, 4 and 5? |
(sigma 2s+, 1 box), (sigma 2s-, 1 box), (pi 2p+, 2 box), (sigma 2p+, 1 box), (pi 2p-, 2 box), (sigma 2p-, 1 box)
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Molecular Orbital Energy Diagrams
Groups 6, 7 and 8? |
(sigma 2s+, 1 box), (sigma 2s-, 1 box), (sigma 2p+, 1 box), (pi 2p+, 2 box), (pi 2p-, 2 box), (sigma 2p-, 1 box)
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hybridization
2 electron groups? |
linear
sp |
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sigma (s) bond
|
results when the bonding atomic orbitals point along the axis connecting the two bonding nuclei
either standard atomic orbitals or hybrids s-to-s, p-to-p, hybrid-to-hybrid, s-to-hybrid, etc. |
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pi (p) bond
|
results when the bonding atomic orbitals are parallel to each other and perpendicular to the axis connecting the two bonding nuclei
between unhybridized parallel p orbitals the interaction between parallel orbitals is not as strong as between orbitals that point at each other; therefore s bonds are stronger than p bonds |
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LCAO method
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the simplest guess starts with the atomic orbitals of the atoms adding together to make molecular orbitals – this is called the Linear Combination of Atomic Orbitals method
weighted sum because the orbitals are wave functions, the waves can combine either constructively or destructively |
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LCAO molecular orbitals
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when the wave functions combine constructively, the resulting molecular orbital has less energy than the original atomic orbitals – it is called a Bonding Molecular Orbital
s, p most of the electron density between the nuclei when the wave functions combine destructively, the resulting molecular orbital has more energy than the original atomic orbitals – it is called a Antibonding Molecular Orbital s*, p* most of the electron density outside the nuclei nodes between nuclei |
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Molecular Orbital Theory
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Electrons in bonding MOs are stabilizing
Lower energy than the atomic orbitals Electrons in anti-bonding MOs are destabilizing Higher in energy than atomic orbitals Electron density located outside the internuclear axis Electrons in anti-bonding orbitals cancel stability gained by electrons in bonding orbitals |
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Bond Order
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Bond Order = ((#bond e-)-(# antibond e-)) / 2
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HOMO
LUMO |
Highest occupied molecular orbital
Lowest unoccupied molecular orbital |
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for molecular orbital pattern, always use the pattern associated with the element in the higher group #.
Example, N=O |
NO uses the pattern 1, 1, 1, 2, 2, 1 following the pattern for O in the 6th group
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MO pattern for C2?
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1, 1, 2, 1, 2, 1 following the pattern for elements in groups 3, 4 and 5
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MO pattern for F2?
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1, 1, 1, 2, 2, 1 following the pattern for elements in groups 6, 7 and 8
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