Pauli Exclusion Principle

Inventor:

 

http://www.nobelprize.org/nobel_prizes/physics/laureates/1945/pauli-bio.html

Wolfgang Pauli was born on the 25th of April, 1900 in Vienna, Austria. He died on the 15th of December 1958 in Zurich, Switzerland.

Pauli Laws:

http://www4.nau.edu/meteorite/meteorite/book-glossarye.html

According to Pauli Exclusion Principle, no two electron can occupy a given quantum state. This means that each electron has its unique set of quantum number. This is not only apply to electron but also to the other fermions like neutrons and protons.
An orbital can hold 0, 1 or 2 electrons only. If there are 2 electrons in an orbital, they must move in opposite spin. Therefore, no two electrons can occupy the same set of four quantum number.

http://www.kentchemistry.com/links/AtomicStructure/PauliHundsRule.htm

THis is incorrect as there must be in opposite direction.

http://www.kentchemistry.com/links/AtomicStructure/PauliHundsRule.htm

This is correct as  the electrons move in opposite spin.