Chapter 8 Electron Configurations and Periodicity

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Chapter 8Electron Configurationsand Periodicity

• Spin Quantum Number
• Electron Configurations
• Periodic Properties

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I. Spin Quantum Number

• Electrons are spinning
• From physics
• Spinning charged particle ? magnetic field
• Electron spin direction in an external magnetic
  field is quantized
• Electron spin quantum number ms

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II. Electron Configurations

• Review Energy Level Diagram for H Atom
• Bohr Model vs. Schroedinger Model
• What about multi-electron atoms?
• New Energy Level Diagrm for Multi-electron Atoms
• Pauli Exclusion Principle
• No two electrons in an atom can have the same
  set of four quantum numbers

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• Electron Configurations
• show where the electrons are probably located
  when an atom is in its ground state
• Key electrons want to be in orbitals with the
  lowest energy
• How do we remember the order?
• Aufbau Diagram
• Easier way Use the periodic table
• Exceptions
• Electron Configurations of Ions
• anions
• cations

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III. Periodic Properties

• Atomic Size
• Down a column
• Across a row
• Ionization Energy
• Definition energy required to remove an
  electron from a gaseous atom (or ion) in its
  ground state
• Electron Affinity
• Ion Sizes