Hybridization & Resonance Flashcards
What does hybridization mean?
Hybridization, kind of like a hybrid car mixing electric power and gas power, is when bound atoms mix higher & lower valence electron orbitals
What kind of orbitals does Carbon have (where are it’s electrons)?
–Carbon forms what kind of orbitals when sp3?
2 electrons in “S” orbital and 2 electrons in “P” orbital
–carbon will form 4 orbitals of equivalence energy when hybridized as sp3
How to determine hybridization
of sigma bonds + # of unbonded electron PAIRS
VSEPR (valence shell electron pair repulsion theory)
Predicts the shape of molecules depending on their repulsion of lone pairs of electrons
What determines shape and bond angle?
Hybridization!
sp hybridization
Linear (180 degrees)
e.g., CO2
sp2 hybridization
- -Trigonal planar (no lone electrons) (e.g., SO3)
- -Bent, 120 degrees, due to one lone electron pair (e.g., SO2, O3, PbCl2)
sp3 hybridization
- Tetrahedral (e.g., CH4, SO4^2-)
- Trigonal pyramidal (e.g., NH3-, H3O+)
- Bent, 109.5 degrees (e.g., H2O, SCl2)
sp3d hybridization
- Trigonal bipyramidal (e.g., SOF4)
- Seesaw (e.g., SF4)
- T shaped (e.g., BrF3)
- Linear (90 degrees/120 degrees or 180 degrees)
sp3d2
- Octahedral
- Square pyramidal
- Square planar (90 degrees)
Resonance structure stability
The structure that has more possible resonance structures will be the most stable
Rules for resonance structures
- Follow octet rule
- Bond moves starting with a lone electron pair, a double bond, or a triple bond
- Make the formal charge the most “comfortable” if a formal charge is unavoidable
- Make structures without formal charges, if possible
How do you determine if a ring molecule is aromatic?
Follow Hückel’s rule: 4n + 2 pi electrons
Characteristics of aromatic compounds
- Conjugated, unsaturated ring system
- High stability due to ability to resonate (e.g., benzene)
- Follows Hückel’s rule: must have exactly 4n + 2 pi electrons
