Electron Location

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					Electron Location


Chapter 5
Lec 5 | MIT 3.091 Introduction
  to Solid State Chemistry
Animations of Electron Levels
 Electron “jumping” website
 Electron levels animation link
 McGraw Hill animation link
    Jumping Electrons
   normally electrons exist in the ground state,
    meaning they occupy the lowest energy level
    possible (the electron shell closest to the nucleus)
   when an electron is excited by adding energy to
    an atom (for example, when it is heated), the
    electron will absorb energy, "jump" to a higher
    energy level
   after a short time, this electron will spontaneously
    "fall" back to a lower energy level, giving off a
    quantum of light energy called a photon
   the key to Bohr's theory was the fact that the
    electron could only "jump" and "fall" to precise
    energy levels, thus emitting a limited spectrum of
    light.
      quantum is the amount of energy required to
       move an electron from one energy level to
       another
Quantum Numbers
   electrons display the properties of both waves and
    particles.
   think of an atom as a very bizarre house (like an
    inverted pyramid) with the nucleus living on the
    ground floor, and then various rooms (orbitals) on
    the higher floors occupied by the electrons
   electrons fill low energy orbitals (closer to the
    nucleus) before they fill higher energy ones
   electron configuration is defined to be the
    arrangement and distribution of electrons in
    atomic orbitals
      the electron configuration of each atom is
       made up of four quantum numbers, which
       describe different properties of each electron
       and its orbital.
Where is an electron?
    What level/size?
    What shape?
    Orientation?
    Spin?




    Quantum numbers give “the address” of the
     electron.
   Principle quantum number (n) - describes the
    SIZE of the orbital or ENERGY LEVEL of the
    atom.
   Angular quantum number (l) - describes the
    SHAPE of the orbital.
   Magnetic quantum number (m) - describes an
    orbital's ORIENTATION in space. This tells the
    placement of the electrons in the sub-orbitals
   Spin quantum number (s) - describes the SPIN
    or direction (clockwise or counter-clockwise) in
    which an electron spins.

				
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posted:12/2/2011
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