Quantum Number

[thanh24mai]

How do you identify the spin projection quantum number?

[Ariana Iranmahboub1G]

The spin projection quantum number (or spin magnetic quantum number), ms, only has two value (+1/2 for an arrow pointing up electron and -1/2 for an arrow pointing down electron) because an electron has two spin states. Since an electron can have either spin state, one electron from a paired electron in an orbital would have ms=+1/2 and the other with ms=-1/2.

[Noah Canio 3C]

As Ariana mentioned, the spin projection quantum number can only be either +1/2 or -1/2 for any electron in a particular orbital. In an electron configuration, +1/2 is indicated by an arrow pointing upwards while -1/2 is indicated by an arrow pointing downwards.

[Eva Zhao 4I]

As said previously, the spin magnetic quantum number (m_s) can be +1/2 or -1/2. It's usually pretty arbitrary, so long as you're aware that no two electrons in the same atom have the same four quantum numbers.