• Aufbau Principle
  • States that electrons are placed in orbitals, subshells, and shells in order of increasing energy when building up the electron configuration.
  • Pauli Exclusion Principle
  • States that no two electrons can have the same set of quantum numbers within an atom.
  • Periods
  • Horizontal rows of the periodic table.
  • Groups
  • Vertical columns of the periodic table.
  • Rutherford's "Gold Foil" Experiment
  • Concluded that all of the positive charge in an atom was concentrated at the center.
  • Heisenberg's Uncertainty Principle
  • States that the exact position and momentum of a particle cannot be simultaneously known
  • Quantum Numbers
  • Describes the positions of the electrons in relation to the nucleus by its shell, subshell, orbital, and spin.
  • Atomic Radius
  • Approximate distance from an atom's nucleus to its valence electrons (Greatest at bottom-left of periodic table).
  • Ionization Energy
  • The energy required to remove an electron from an atom (Greatest at top-right of periodic table).
  • Dmitri Mendeleev
  • Creator of the Periodic Table of Elements.