The Atom: Quantum Mechanics

Born, Planck, Heisenberg and Schrondinger built on the work of Rutherford to develop the Quantum Mechanical Model of the Atom.  Here are the primary points:

1. Energy is ultimately quantized into small discrete packet that we call photons.
2. Electrons can absorb (gain) or emit (lose) photons, but they can't use or lose a portion of a photon.
   - When an electron gains/absorbs a photon it will become excited and jump to a higher energy level.
   - When an electron loses/emits a photon it will has less energy and jump to a lower energy level.
   - Electrons DO NOT MOVE (Newtonian concept), they JUMP.  They cannot use a portion/fraction of a photon.  It's all or nothing.
   - When electrons jump from one energy level to another, it is called a Quantum Leap.  They have gained or lost a quantized amount of energy- a photon.
3. Heisenberg Uncertainty Principle- (basic) The exact velocity and location of an electron cannot be determined without changing its velocity and/or location.  We can only determine an electron's probable location in the electron cloud.  This probable position is explained by the 4 Quantum Numbers.
4. Quantum Numbers
• Principle Quantum Number describes the distance from the nucleus, or the energy level.
• Orbital Quantum Number describes the shape of the electron cloud.
• Magnetic Quantum Number describes the orientation of the electron cloud in space with respect to the 3 axis.
• Spin is a notation of up/down to represent that the electrons within a pair will always be as far apart as possible (Remember- like charges repel).
5. Pauli Exclusion Principle- No 2 electrons in the same atom can have the same 4 Quantum Numbers.  A pair of electrons in the same atom will be in the same energy level, shape and orientation, but they will always be as far apart as possible.