Confused about the Pauli Exclusion Principle....

[Lance Fernandes]

The principle states that two electrons cannot have the same quantum numbers. And I've read that this applies to "fermions"- protons, neutrons, 1/2 spin particles. But how exactly does this apply to, say, a proton? Sorry if I sound stupid...I've got all my knowledge about this through the internet. I'm in the 10th grade as well. So I'm not too fimiliar with the complex stuff :') Thanks!

 

[bhobba]

The same way for any spin 1/2 particles - it matters not as far as this is concerned

There is this thing called a quantum state which is a property quantum particles have. It allows us to predict the probabilities of the outcomes of observations. There is a very important theorem of the most advanced form of quantum theory, called Quantum Field Theory, known as the spin statistics theorem:
http://www.worldscientific.com/worldscibooks/10.1142/3457#t=aboutBook

What this theorem says, is for spin 1/2 particles, no two particles can be in exactly the same state - its called the Pauli Exclusion Principle

This has all sorts of interesting consequences. For example the states of electrons (they are spin 2 particles) in atoms can only take on certain values - usually described by the energy in those states. But since no two electrons can be in the same state they get filled up from the lowest energy to the highest. If you try to push two atoms together they attempt to fill up states already filled - but the exclusion principle says you can't do that. It resits it and says - no. In fact this is the very origin of solidity:


For protons check out the following:
http://hyperphysics.phy-astr.gsu.edu/hbase/nuclear/shellpau.html

Thanks
Bill