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Spin Magnetic Quantum #

Posted: Fri Oct 18, 2019 2:24 am
by Selena Yu 1H
Why is the spin magnetic quantum number only either +1/2 or -1/2? Was this found through experiments? Is it possible for it to be any other number?

Re: Spin Magnetic Quantum #

Posted: Fri Oct 18, 2019 9:29 am
by Deepika Reddy 1A
The spin quantum number is just used to differentiate between the two electrons in an orbital and it is needed to completely describe an electron state. One of the electrons in an orbital is facing up and the other is facing down. The spin quantum number just tells us which is which and makes it so that no electron in an atom has the same four quantum numbers as any other electron in the atom. The positive 1/2 is used for upward spin electrons and the downward facing spin is negative 1/2.

Re: Spin Magnetic Quantum #

Posted: Tue Oct 22, 2019 12:10 pm
by Rohit Ghosh 4F
While we can say that an electron spins "up" or "down," that is actually arbitrary. In reality, electron spin is more complicated than just spinning in one direction or another.

Re: Spin Magnetic Quantum #

Posted: Tue Oct 22, 2019 1:32 pm
by Robert Tran 1B
There are only two possibilities for the spin direction of an atom: upwards and downwards. Because of this, there are also only two possible spin magnetic quantum numbers. I believe the numbers +1/2 and -1/2 were chosen somewhat arbitrarily.

Re: Spin Magnetic Quantum #

Posted: Tue Oct 22, 2019 3:22 pm
by Kallista McCarty 1C
The spin number can only be +1/2 or -1/2. Lavelle didn't go into much detail into explaining the experiments and the way in which this was determined because it does not pertain to our class. All that we need to know is that +1/2 is spinning up while -1/2 is spinning down!

Re: Spin Magnetic Quantum #

Posted: Thu Oct 24, 2019 3:45 pm
by KDang_1D
Yes, the concept of electron spin was discovered through the Stern Gerlach experiment. They fired silver atoms, which have 1 valence electron, through a pair of magnetized plates. The interaction between the local magnetic fields of the individual electrons and the plates' magnetic field caused the Ag atoms to land on the detector in two distinct regions. This lead to the conclusion that electrons have 2 spin states, +1/2 and -1/2. The choice of the 1/2 value could be arbitrary like l=0, 1, 2,3, etc. and ml=0, +/-1, +/-2, etc., but I'm not sure.

Re: Spin Magnetic Quantum #

Posted: Sun Nov 03, 2019 11:59 pm
by Ethan Low 1L
Yeah the number can only be -1/2 or +1 and at the review session they mentioned that its important to include the positive/ negative sign to signify direction of spin.