Presentation on theme: "Molecular Geometry and Bonding Theory"— Presentation transcript:
1Molecular Geometry and Bonding Theory Chapter 9 AP Chemistry
2Molecular GeometryMolecular Geometry- general shape of a molecule as determined by the relative position of the nuclei.The geometry and size of a molecule helps to determine it’s chemical behavior.VSEPR- Valence-Shell-Electron-Pair-Repulsion model- predicts geometry based upon e’s around the central atom.
3Principles of the VSEPR theory Electrons are kept as far away from one another as possible – minimizing e pair repulsionsElectron pairs are considered as being bonding or non-bonding (lone pairs)A multiple bond counts as a single bonding pairElectron pair geometry is described by the regions of e’s around the central atomMolecular geometry is a consequence of electron pair geometry.
4Predicting Structures VSEPR Derive the Lewis Structure to the form AXmEnA = central atomX = atoms bonded to the central atomE = lone pairs of e’s on the central atomM = # of bonded atomsN = # of lone pairs
5Electron Geometry Linear ExampleElectron and Molecular Geometry LinearBond angles 180Sp HybridNon-polar
26Molecular Geometry: AX4E1 Pyramidal Planar Example XeOF4
27Molecular Geometry: AX4E2 Square Planar Example XeF4
28Bond AnglesNon-bonding pairs of e’s take up more space (att. by one nucli) than bonded e pairsDouble and triple bonds take up more space than single bonds (more e’s)Volume occupied lone pairs > triple bonds > double bonds > single bonds
29ForcesNon-bonding pairs exert repulsive forces on adjacent e pairs and compress anglesMultiple bonds also exert repulsive forces and compress angles