C121 11-3 lec29GL

C121 11-3 lec29GL - Lecture 29 November 18, 2011 Bonding:...

Info iconThis preview shows pages 1–7. Sign up to view the full content.

View Full Document Right Arrow Icon

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

View Full DocumentRight Arrow Icon

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

View Full DocumentRight Arrow Icon

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

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

Unformatted text preview: Lecture 29 November 18, 2011 Bonding: Specific Models Last Day: II Molecular Orbital Theory (14.2-14.4) Today: II Molecular Orbital Theory (14.2-14.4) (contd) Intermolecular Forces (Chapter 16) Molecular Orbital Diagram for H 2 Molecule 1s 1s * Molecular orbital e- configuration for H 2 : ( 1s ) 2 Bond Order, Bond Strength, Bond Length Recall, earlier definitions of bond order: Bond order = # shared e- (2e- per bond) or Bond order = # bonds/# of sites M.O. Definition: Bond Order = (# e- in bonding M.O.s - # e- in anti-bonding M.O.s) As bond order increases: bond strength (bond dissociation energy) increases bond length decreases M.O. Electron Configurations for First Row Diatomics monatomic species does not exist (2-2)/2 = 0 ( 1s ) 2 ( 1s * ) 2 2(2) = 4 He 2 108 251 (2-1)/2 = ( 1s ) 2 ( 1s * ) 1 2(2)-1 = 3 He 2 + highly unstable (2-1)/2 = ( 1s ) 2 ( 1s * ) 1 2(1)+1 = 3 H 2- 74 436 (2-0)/2 = 1 ( 1s ) 2 2(1) = 2 H 2 106 255 (1-0)/2 = ( 1s ) 1 2(1)-1 = 1 H 2 + Bond Length (pm) D(X-X) (kJ/mol) Bond Order MO Electron Configuration # Valence Electrons Molecule /Ion Constructing MO Diagrams for Second Row Diatomic Molecules First, we must construct molecular orbitals from the valence atomic orbitals available to the second row elements: Thus each atom in the diatomic molecule contributes 4 valence atomic orbitals for a total of 8 atomic orbitals Therefore, we can construct a total of 8 molecular orbitals 2p x 2p y 2p z 2s 2p 2s 2s + 2s 2s- 2s 2s * bonding...
View Full Document

This note was uploaded on 12/10/2011 for the course CHEM 121 taught by Professor Leech during the Fall '11 term at Simon Fraser.

Page1 / 24

C121 11-3 lec29GL - Lecture 29 November 18, 2011 Bonding:...

This preview shows document pages 1 - 7. Sign up to view the full document.

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