Question

What's the Pauli-exclusion Principle?

Asked by: Wolfgang M.

Answer

In 1925, Wolfgang Pauli gave physics his exclusion principle as a way to explain the arrangement of electrons in an atom. His hypothesis was that only one electron can occupy a give quantum state. That is, each electron in an atom has a unique set of quantum numbers (the principle quantum number which gives its energy level, the magnetic quantum number which gives the direction of orbital angular momentum, and the spin quantum number which gives the direction of its spin). If this principle did not hold, all of the electrons in an atom would pile up in the lowest energy state (the K shell). In fact, we now know that that the Pauli exclusion principle holds for not just electrons but for any fermions (half-integer spin particles like electrons, protons, neutrons, muons, and many more.)

Answered by: Joseph Kozminski, B.S., Physics Grad Student, MSU, East Lansing, MI

Search

Loading






Science Quote

'There is no inductive method which could lead to the fundamental concepts of physics. Failure to understand this fact constituted the basic philosophical error of so many investigators of the nineteenth century.'

Albert Einstein
(1879-1955)

Top Selling

Here are our physics & astronomy bestsellers:
Magnetic Levitator - Classic
KonusScience 5 Way Microscope Kit
Tin Can Robot 4M Kit
CHEM C1000 Chemistry Kit v2.0
Periscope
Potato Clock 4M Kit
Revolving Multi-Color Fiberoptic Light
3D Magnetic Field Tube
Top Secret - Spinning Top
4M Kitchen Science Kit

Sponsors

USC University of Southern California Dornsife College Physics and Astronomy Department McMaster University Physics and Astronomy Department