Question #a7fdc

1 Answer
Stefan V.
Feb 7, 2018

#m_l = 0#

Explanation:

Start by writing the electron configuration of a neutral sodium atom.

#"Na: " 1s^2 2s^2 2p^6 3s^1#

The last electron in a neutral sodium atom is added to the #3s# subshell, which, as you know, contains a single orbital, the #3s# orbital.

Now, the magnetic quantum number, #m_l#, tells you the orientation of the orbital in which an electron is located inside an atom.

In the case of an #s# orbital, the magnetic quantum number can only take one value.

#m_l = 0 #

This is the case because the value of the magnetic quantum number depends on the value of the angular momentum quantum number, #l#.

#m_l = {-l, - (l-1), ..., -1, 0, 1, ..., (l-1), l}#

The angular momentum quantum number tells you the shape of the orbital(s), i.e. the energy subshell in which the electron is located.

An #s# subshell is denoted by

#l = 0#

which implies that the magnetic quantum number can only take one possible value here.

#l = 0 => m_l = 0#

This tells you that an #s# subshell contains a single orbital, the #s# orbital.

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