Chapter 3: 3.4 Valence Bond Theory Flashcards
What is the purpose of the Valence Bond Theory?
Explains the discrepancies between the VSEPR-predicted or experimentally observed shapes and those predicted by the geometries of the pure atomic orbitals
What are the VB Theory Principles?
Covalent bonds formed by two orbitals overlap with electrons of opposite spin
Electrons in bonds are localized
Orbitals may hybridize before bond formation
Define:
Hybridization
The mixing of the pure atomic orbitals in such a way as to produce “hybrid” orbitals whose shape is consistent with the observed geometry of the bonds
Define:
Sigma Bond
A bond formed by the overlap of orbitals in a region of space that lies on the same axis as the two nuclei (head-on overlap)
List hybrid orbitals formed and electronic arrangement for 2 regions of electron density
Hybrid Orbitals: Two sp
Electronic Arrangement: Linear
List hybrid orbitals formed and electronic arrangement for 3 regions of electron density
Hybrid Orbitals: 3 sp2
Electronic Arrangement: Trigonal Planar
List hybrid orbitals formed and electronic arrangement for 4 regions of electron density
Hybrid Orbitals: Four sp3
Electronic Arrangement: Tetrahedral
List hybrid orbitals formed and electronic arrangement for 5 regions of electron density
Hybrid Orbitals: 5 sp3d
Electronic Arrangement: Trigonal Bipyramidal
List hybrid orbitals formed and electronic arrangement for 6 regions of electron density
Hybrid Orbitals: Six sp3d2
Electronic Arrangement: Octahedral
Define:
Pi bond
A bond formed by the side-on overlap of the leftover p orbital, atoms involved cannot rotate
A single bond is always a:
Sigma bond
A double bond is always:
A sigma bond and a pi bond
A triple bond is always:
A sigma bond and 2 pi bond
