1. Hybridization of Orbitals
Chap 9
Hybridization of Orbitals

2. What is Hybridization?
Mixing of native orbitals to form special bonding orbitals
Modifies the “localized electron model” (aka Lewis Structure) to show special atomic orbitals used in forming molecules
Orbitals can overlap to form the bonds – helps with the electron sharing
Combinations of s, p, & d orbitals
Bonding primarily involves the valance electrons, which comes from the s or p orbitals

3. Types of hybridization
sp3 hybridization: combination of 1-s and 3-p orbitals
4 sp3 hybrid orbitals
4 pairs e- around center atom
tetrahedral or triangular pyramid
sp2 hybridization: combination of 1-s and 2-p orbitals
3 sp2 hybrid orbitals
3 pairs e- around center atom
trigonal planar

4. sp hybridization: combination of 1-s and 1-p orbital 2 sp hybrid orbitals 2 pairs e- around center atom linear dsp3 hybridization: combination of 1-d, 1-s and 3-p orbitals 5 dsp3 hybrid orbitals 5 pairs e- around center atom trigonal bipyramidal d2sp3 hybridization: combination of 2-d,1-s and 3-p orbitals 6 d2sp3 hybrid orbitals 6 pairs e- around center atom octahedral

5. Specific covalent bonding
Sigma (σ) bonds – electrons occupy space directly between atoms (center line)
Pi (π) bonds - electrons occupy space above or below center line joining atoms
Single bonds = sigma bonds
Double bonds = 1 sigma & 1 pi bonds
Triple bonds = 1 sigma & 2 pi bonds

6. Photoelectron spectroscopy (PES)
Can be used to determine the relative energies of electrons in individual atoms and molecules or ID element
Photoelectric effect = light shined on metal causes electrons to be ejected/emitted
Higher frequency of light causes more electrons to be emitted.
Higher frequency = higher energy
E=hν
binding energy of electrons is determined through PES
High energy incident light (X-ray or UV) is used to eject a single electron then measure KE of electron
Every “kind” of electron has a binding energy
subshells

7. PES continued
Binding energy = difference between incident light and KE of ejected electron
When many atoms are hit with incident light, many electrons are emitted. A combined binding energy for the electrons then gets plotted on a photoelectron spectrum.
X-axis = binding energy (ionization energy) (decreases left to right)
Y-axis = relative number of electrons
One peak for each “kind” of electrons
Peak height corresponds to number of electrons of that “kind”
As effective nuclear charge increases (number of protons), the binding energy increases

8. Each peak corresponds to a set number of electrons.
Should correlate with the electron configuration of an element.
4 peaks = 4 orbitals in the electron configuration or orbital diagram
1s, 2s, 2p, 3s