1 / 30

Molecular Orbitals in Chemical Bonding

Molecular Orbitals in Chemical Bonding. Molecular Orbital Theory. Types of molecular orbitals that can be produced by the overlap of atomic orbitals. Head-on overlap of atomic orbitals produces s (sigma) orbitals. Side-on overlap of atomic orbitals produces p (pi) orbitals.

rhoda
Download Presentation

Molecular Orbitals in Chemical Bonding

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Molecular Orbitals in Chemical Bonding

  2. Molecular Orbital Theory • Types of molecular orbitals that can be produced by the overlap of atomic orbitals. • Head-on overlap of atomic orbitals produces s (sigma) orbitals. • Side-on overlap of atomic orbitals produces p (pi) orbitals. • Two s atomic orbitals can overlap and produce two molecular orbitals designated as a ssand ass*molecular orbital.

  3. Molecular Orbital Theory • Graphically we can represent this as

  4. Molecular Orbital Theory

  5. Molecular Orbital Theory

  6. Molecular Orbital Theory • The head-on overlap of two corresponding p atomic orbitals on different atoms, say px with px produces sp and sp*molecular orbitals.

  7. Molecular Orbital Theory

  8. Molecular Orbital Theory • Side-on overlap of two corresponding p atomic orbitals on different atoms (say py with py or pz with pz) produces p and p*(pi) molecular orbitals.

  9. Molecular Orbital Theory

  10. Molecular Orbital Energy-Level Diagram • Order of filling of MO’s obeys same rules as for atomic orbitals. • Including • Aufbau principle • Hund’s Rule

  11. Molecular Orbital Energy-Level Diagram

  12. Bond Order and Bond Stability • Bond order (bo) of a molecule is defined as half the number of electrons in bonding orbitals minus half the number of electrons in antibonding orbitals

  13. Homonuclear Diatomic Molecules • Consider the overlap of the atomic orbitals of two nitrogen atoms to form an N2 molecule. • Each N atom has 7 electrons thus the N2 molecule has 14 electrons.

  14. Homonuclear Diatomic Molecules

  15. Homonuclear Diatomic Molecules • In shorthand notation we represent this configuration as

  16. Homonuclear Diatomic Molecules • The greater the bond order of a bond the more stable we predict it to be. • For N2 the bond order is

  17. Homonuclear Diatomic Molecules • MO treatment can also be applied to ions. • Ions are charged and that charge affects the stability as well as the bond order. • Write out the electron configuration of the N2+ ion in abbreviated notation (s1s2s1s*2……). What is the bond order?

  18. Homonuclear Diatomic Molecules • Write out the electron configuration of the N2+ ion in abbreviated notation (s1s2s1s*2……). What is the bond order?

  19. Homonuclear Diatomic Molecules • Write out the electron configuration of the O2 molecule in abbreviated notation. What is the bond order? Is the molecule paramagnetic or diamagnetic?

  20. Homonuclear Diatomic Molecules • Write out the electron configuration of the O2 molecule in abbreviated notation. What is the bond order? Is the molecule paramagnetic or diamagnetic?

  21. Homonuclear Diatomic Molecules • Write out the electron configuration of the Be2 molecule in abbreviated notation. What is the bond order? Would you predict that the molecule exists? You do it!

  22. Homonuclear Diatomic Molecules • Write out the electron configuration of the Be2 molecule in abbreviated notation. What is the bond order? Would you predict that the molecule exists?

  23. Homonuclear Diatomic Molecules • Write out the electron configuration for F2. In this molecule thespmolecular orbital is lower than theppmolecular orbitals. What is the bond order? Is F2 paramagnetic?

  24. Homonuclear Diatomic Molecules • Write out the electron configuration for F2. In this molecule thespmolecular orbital is lower than theppmolecular orbitals. What is the bond order? Is F2 paramagnetic?

  25. Delocalization and Shapes of Molecular Orbitals • Valence bond theory discusses resonance formulas. • Carbonate ion (CO32-) is an example.

  26. Delocalization and Shapes of Molecular Orbitals • Molecular orbital theory describes shapes in terms of delocalization of electrons. • Again carbonate ion (CO32-) is a good example.

  27. Delocalization and Shapes of Molecular Orbitals • The structure of benzene is described well by molecular orbital theory.

  28. Delocalization and Shapes of Molecular Orbitals • Resonance structure - VB theory.

  29. Delocalization and Shapes of Molecular Orbitals • Molecular orbital theory

  30. Delocalization and Shapes of Molecular Orbitals • Molecular orbital theory

More Related