Chapter8

Chapter8

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Unformatted text preview: Chapter 8: Electron Configurations and the Periodic Table Chem 6A, Section D Oct 25, 2011 Chem 6A Michael J. Sailor, UC San Diego 1 The Periodic Table of the Elements Chem 6A Michael J. Sailor, UC San Diego 2 Electron Configurations Aufbau ="Building up" As each proton is added to the nucleus, you add an electron to the hydrogen-like orbitals. Add to s, then d, then p orbitals of the same principle quantum number 3 Chem 6A Michael J. Sailor, UC San Diego Quantum numbers Quantum Number Called Describes n l Principle quantum number SIZE and ENERGY Angular momentum (Azimuthal) quantum number SHAPE ml Magnetic quantum number ORIENTATION ms Electron spin quantum number INTRINSIC ANGULAR MOMENTUM OF THE ELECTRON Chem 6A Michael J. Sailor, UC San Diego 4 The Periodic Table of the Elements 5 Chem 6A Michael J. Sailor, UC San Diego The Periodic Table of the Elements 1s 2s 3s 4s 5s 6s 7s 3d 4d 5d Chem 6A Michael J. Sailor, UC San Diego 2p 3p 4p 5p 6p 6 Electron Configurations How to fill up orbitals with electrons? • Electrons go in lowest energy orbital first, they spread over all the empty orbitals with the same spin, then they pair up. • Pauli Exclusion Principle: No more than 2 electrons per orbital, must be of opposite spin. • Hund's rule: When there is more than one orbital with the same energy, fill up empty orbitals first, keeping the spins the same. 7 Chem 6A Michael J. Sailor, UC San Diego The Building-up Principle (aufbau) Pauli exclusion principle: no more than 2 electrons in each orbital. Pairs of electrons in the same orbital must have opposite spins. Hund’s rule: When there is more than one orbital with the same energy (degenerate), fill up empty orbitals with one electron before pairing the electrons, keep the spins the same. from T. Moeller “Inorganic Chemistry” Wiley 1952 9 Similar figure in your textbook Chem 6A Michael J. Sailor, UC San Diego 8 Stern-Gerlach Experiment: Ag atoms Screen OVEN Containing Ag Magnet The atoms split into two paths in a magnetic field This experiment tells us that each individual electron has a magnetic moment; there must be a 4th quantum number: Electron spin, or ms Chem 6A Mi...
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This note was uploaded on 11/16/2011 for the course CHEM 6A taught by Professor Pomeroy during the Spring '08 term at UCSD.

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