hybridized orbitals

1. Lewis structures/VSEPR/FC
• Count electrons in
• Basic attachments
• Subtract electrons used in attachments
• Put electrons on outer atoms
– Extra electrons go on inner atom
– Deficient in electrons – use multiple bonds
• May have resonance structures
• FC may help determine which is more reasonable (e- in bonds go
to higher e- neg atom)
• e- positions determine e- shape around central atom
• Atom positions determine shape of molecule

2. Names of shapes:
Electron positions – “lone” (unshared pairs) prefer “more room”
Especially important in trig bipyramidal and octahedral

5. Bond angles – determine after placing ALL electrons
C – 4 bonds, N and O total of 4 pr electrons

6. Bond angle
Shape of electrons
Shape of atoms connections

7. d- orbitals will be used in expanded octets

8. hybridization
• VSEPR predicts bond angles but in 1930’s
Linus Pauling used atomic orbitals to to
predict these same bond angles
– Valence bond theory hybridized orbitals
– Atomic orbitals do not have these shapes
• Hybridized orbitals – belong to molecules

9. When atoms form molecules
• Electrons are more “directional”

10. C 1s 2s 2p 1s 2s 2p
_ _ ___ _ _ ___
Explanation for bond angles seen in molecules

12. Hybridization
• s, p, d shapes fit the same shapes and bond
angles as VSEPR
Add to your chart
Fig 7.4 Pg 177 fig 7.5

13. CN Shape (VSEPR) hybridization
2 Linear sp
3 Trigonal planar sp2
4 Tetrahedral sp3
5 Trigonal bipyramid sp3d
6 octahedral sp3d2

14. Add hybridization
Bond angle
Shape of electrons
Shape of atoms connections
Note: electrons not added
Are all electrons added?

15. σ and π bonding
• Single bonds – sigma – end to end overlap of
orbitals – electron density between nuclei
• Multiple bonds – 1 sigma and 1or 2 pi bonds
• Pi bonds – side to side overlap – electron
density above and below nuclei
• Pi bonds weaker than sigmas
– Therefore double bond less than twice as strong
as single bond

16. C2 H4
FIX FOR SP2

17. Acetylene – 1 sigma, 2 pi’s
C2 H2

19. Pi bonds
• Overlap of unhybridized p orbitals
• C2H6 C2H4 C2H2

21. Delocalized electrons
• Pi orbitals can be delocalized over several
atoms
• Alternating =‘s

22. Place H’s and e-’s
Box sp3
Triangle sp2
Circle atoms with delocalized pi electrons
O
H3C
NH
NH O

23. CH3 CH3 8
H3C CH3
9 7
H
OH 12 10 NH
13 11 5 6
H
CH3 14 16 4
15 3
HN 2
1
NH2
HO
N
HO H N
HO H
NH N
HO H
H H
H3C N N O
NH
H3C N
O