Superman and b159510:

Jsorex was the one with the "correctest" explanation so far, I think - although he did not exactly hit the nail on its head - but at least he used the hammer "quantum number = sum of electron states" - the right kind of tool...

Quantum numbers distinguish between particles and their states (note the plural!). Besides quantum numbers depicting common quantities like spin

s or charge

Q, there are also a few others:

Angular track momentum

LIsospin

ICharm

cOverall spin

Jz-component of the isospin

I_{3}Strangeness

Sz-component of the spin

S_{z}baryon number

Bhyper charge

Hlepton number

LAccording to Pauli, the electronic states of a single atom must only be occupied in a way that allows for not more than 2 electrons to correlate in all quantum numbers. This implicates that for example with helium, one electron has to have an up-spin (s=+1/2) while the other must have a down-spin (s=-1/2).

Particles (read: electrons too) can only take on an angular momentum of

n/2 * **h_** = h/2*pi* (h = Planck quantum effect number

(?translation?)).

So the smallest spin unit is x*

**h_**/2 (with x=1), and the number representing the factor x is called the quantum number in this case.

To indicate the spin of a particle, it therefore suffices to give the factor with which

**h_** has to be multiplied to give the spin.

**This number is also called the quantum spin number s**.

There are particles with fermionic spin (numbered h/2, 3h/2, 5h/2 etc.) and bosonic spin (numbered 0, h, 2h, 3h etc.).

Other quantum numbers are numbered like this, for example: charge Q is either a multiple of the elemental charge

*e* or 1/3rd of it, the maximum value of the isospin I is n/2-1/2 with n being the number of particles forming a theoretical nucleon (i.e. neutron and proton, where n=2); the hyper charge H is calculated from charge Q and isospin I

_{3} according to the formula Y = 2(Q - I

_{3}) (i.e. proton and neutron have the same hyper charge!) - strangeness S and charm C are quantum numbers solely used for differentiating between quarks...

Hope this helps.

(Superman: you maybe could've used GOOGLE to read about it: search for "quantum number pauli principle"

...

b159510: of course I'm a bit disappointed, because of your nickname, and, well - you know what I mean...

)

...and to complete your confusion: the quantum number of a complex particle is the sum of its modules quantum numbers.

(And of course quantum numbers just depict particle states that can only be described in portions or quantums - not necessarily just their detention probability/orbital shape, but also track angular momentum I, being quantified into the quantum numbers 1,2,3,4,5 etc. (being correspondant to S,P,D,F,G,H etc)...

)

_{indole_amine}