chapter 2 - CHM361 INORGANIC CHEMISTRY Chapter 2 Valence Bond Theory 1 Topic content 2.1Lewis Structures 2.2Valence Shell Electron Pair Repulsion

chapter 2 - CHM361 INORGANIC CHEMISTRY Chapter 2...

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CHM361 INORGANIC CHEMISTRY Chapter 2 Valence Bond Theory 1
Topic content 2.1Lewis Structures 2.2Valence Shell Electron Pair Repulsion Theory (VSEPR) 2.3Valence Bond Theory 2.4Orbital Hybridization: sp 3 , sp 2 sp, sp 3 d and sp 3 d 2 2
At the end of lesson student should be able apply and solve the problems regarding on: Orbital hybridization Valence Bond Theory (VBT) Hybridization Of Atomic Orbital (sp 3 , sp 2 sp, sp 3 d and sp 3 d 2 ) The Mode of Orbital Overlap Types of Covalent Bonds. 3
LEWIS STRUCTURE Visualizing what molecule look like- convert molecular formula to Lewis structure Only valence electrons are important in bonding. Lewis dot structures show valence electrons surrounding atom. 4
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# Rules for writing Lewis symbol for covalent bonding 1. Choose the most symmetry structure 2. Calculate N value . N is the number of needed electrons for the entire atom to achieve octet structure. 3. Calculate the A value . A is the number of available electrons of each atom in the compound. 4. Calculate S . S is the number of shared electrons between the atoms by using the following formula: S=N-A 6
Example : Lewis structure for CO 2 1.Choose the most symmetry structure. 7
How does bond form? 8
This theory can also be applied to molecules with more than two atoms such as water. Each covalent bond results in a new combined orbital with two oppositely spinning electrons. In order for atoms to bond according to the valence bond model, the orbitals must have an unpaired electron. Strength of bonding depends on the amount of overlap : the greater the overlap, the stronger the bond 9
VSEPR The familiar VSEPR (Valence Shell Electron Pair Repulsion) approach to molecular structure was developed by Ronald Gillespie. The basic idea is that lone pairs of electrons occupy space around a central atom in much the same way as do atoms that are bonded to the central atom.

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