Unit 7: bonding theories Flashcards
VSEPR?
Valence-Shell electron pair repulsion theory
VBT?
Valence Bond Theory
What does VSEPR model do?
- Structure around a given atom is determined by minimizing repulsions between electron pairs
- Predicts geometry and bond angles
Charged clouds?
Can either be:
- Single bond
- Multiple bond
- Lone pair of electrons
- Single electrons
So if there is 3 bonding pairs and 1 lone e- pair, it’s 4 charged clouds!
The 5 VSEPR models?
- Linear
-Trigonal planar - Tetrahedral
- Trigonal bipyramid
- Octahedral
2 charged electrons?
- Linear model
- Bong angle of 180 degrees minimizes electron pair repulsion
- Ex: CO2 and HCN
3 charged clouds?
- Trigonal planar model
- Bond angles of 120 degrees minimize electron pair repulsion
- Can also have a bent structure
4 charged clouds?
-Tetrahedral model
- Bond angles of 110 degrees to minimize electron pair repulsion
- Can also be trigonal pyramid and bent structure
5 charged clouds?
- Trigonal bipyramidal
- Expanded octet with 5 electrons pairs
- 3 equitorial (120) and 2 axial (90)
- Can also be seasaw, T-shape or linear
6 charged clouds?
- Octahedral
- expanded octet with 6 electron pairs
- can also be square pyramidal or square planar
Valence bond theory?
- Describes how electrons are shared
- Involves hybridizing orbitals
- Predicts type of bonding and explains propreties!
Sigma bond?
When atoms form bonds, the atomic orbitals of their valence electrons involved with bonding overlap and combine to produce new combinations of orbitals.
- SINGLE BOND mainly, but also present in double and triple bonds
How will F + F form F2?
-The 2 pz1 on each atom will bond together to form 2pz2 (full)
Ground state electron configuration?
- Nothing is done to the electrons, not energized
Hybridization steps?
(Example for sp3)
1- An electron is promoted to a higher orbital (energizes it’s own electron)
2- Nonequivalent orbitals, so second hybridization so bonds are equivalent
3- Hybridized configuration (sp3 for tetrahedral structures)
