The four levels of organization to describe location of electron

1. Principal energy level: describes in very general terms how far away form the nucleus an electron can be found. It is given the symbol n
2. Sub level: there are four different sub levels called s, p, d, and f.

• The first principal energy level has only one sub level called the 1s
• The second principal energy level has two sub levels called 2s and 2p
• The third principal energy level has three sub levels called 3s, 3p, and 3d
• the fourth and all subsequent principal energy levels have four sub levels

       3. Orbitals: The s sub level contains only one orbital, which is shaped like a sphere. The p sub                 level contains three orbitals, which are shaped like dumb-bells and are oriented around the x,                y, and z axis. The d sub level contains five orbitals and the f sub level contains seven orbitals        4. Spin: each orbital can hold two electrons, each with opposite spins. One has an upward spin,                 and the other has a downward spin.

http://chemwiki.ucdavis.edu/Core/Inorganic_Chemistry/Electronic_Structure_of_Atoms_and_Molecules/Electronic_Configurations

helpful study links
http://www.kentchemistry.com/links/AtomicStructure/Sublevels.htm

http://www.chemicool.com/definition/sublevel.html