CH 301 - Chapter 13-14 part 3 Lecture Notes

CH 301 - Chapter 13-14 part 3 Lecture Notes - Chapter 14-II...

Info iconThis preview shows pages 1–14. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Chapter 14-II • Section 14-I: Valence Bond Theory • useful for deriving shapes/polarity • simple but inaccurate/deficient (see previous set of lecture figures) • Section 14-II: Molecular Orbital Theory more complex/more accurate all valence electrons are delocalized
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 Chapter 14 Part II: Molecular Orbitals 1. Molecular Orbitals 2. Molecular Orbital Energy Level Diagrams 3. Bond Order and Bond Stability 4. Homonuclear Diatomic Molecules 5. Heteronuclear Diatomic Molecules 6. Delocalization and the Shapes of Molecular Orbitals
Background image of page 2
3 Molecular Orbital Theory • Combinations of atomic orbitals on different atoms form molecular orbitals (MO’s). • Electrons in MO’s belong to the molecule as a whole . • Treat orbitals as “wavefunctions” and electrons as waves of energy.
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
4 Molecular Orbitals There are two simple types of molecular orbitals that can be produced by the overlap of atomic orbitals. 1. Head-on overlap of atomic orbitals produces σ (sigma) orbitals. 2. Side-on overlap of atomic orbitals produces π (pi) orbitals. Two 1s atomic orbitals that overlap produce two molecular orbitals designated as: 1. σ 1s or bonding molecular orbital 2. σ 1s * or antibonding molecular orbital.
Background image of page 4
5 • Graphically these two orbitals look like this:
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
6 Overlap of Wavefunctions
Background image of page 6
7 Constructive Overlap of two 1s orbitals Destructive Overlap of two 1s orbitals
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
8 Bonding orbital Anti-bonding orbital Lower energy Higher energy Stable Unstable Favorable for electrons Unfavorable for electrons Electrons exist between nuclei Electrons exist outside
Background image of page 8
9 Energetically, the molecular orbitals split. 1. The σ 1s lies lower in energy. 2. The σ 1s * is higher in energy. Molecular orbital diagram for the union of two s orbitals
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
10 The head-on overlap of two corresponding p atomic orbitals on different atoms, such as 2p x with 2p x , produces: 1. bonding orbital 2. antibonding orbital x 2p * σ x 2p σ
Background image of page 10
11 • Graphically, these orbitals look like this:
Background image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
12 Side-on overlap of two corresponding p atomic orbitals on different atoms (such as 2p y with 2p y or 2p z with 2p z ) produces: 1. or (both are bonding orbitals) 2. or (both are nonbonding orbitals) y 2p π z 2p π y 2p * π z 2p * π
Background image of page 12
13 • Graphically these orbitals look like this:
Background image of page 13

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 14
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 60

CH 301 - Chapter 13-14 part 3 Lecture Notes - Chapter 14-II...

This preview shows document pages 1 - 14. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online