1. QUESTION:
Which of the following is not an allowed value of the magnetic quantum number (ml) for an electron in a 3d orbital? A. 3, B. 2, C. 0, D. -1
Allowed values of magnetic quantum number (ml) are integers from –l to +l, where l is the orbital quantum number.
Code letters for orbital quantum number (l): l=0: s. l=1: p l=2: d l=3; f l=4; g
For an electron in a 3d orbital: l=2, and the allowed values of ml are: -2, 1, 0, 1, and 2
SCRIPT
Which of the following is not an allowed value of the magnetic quantum number…. Em sub ell… for an electron in a three dee orbital?
3,…2,…0,…., or negative one.
PAUSE 2 SECONDS
CLICK
Values for the magnetic quantum number… em sub ell… are restricted to integers starting from negative ell, up to positive ell,
Where ell is the orbital quantum number.
CLICK The letter in the name of an orbital implies the value of the orbital quantum number.
For Ess orbitals, ell is equal to zero.
For pee orbitals, ell is equal to one
For dee orbitals, ell is equal to two,
And so on.
In this case, we are being asked about the three dee orbital. Therefore, ell is equal to two.
And the allowed values of em sub ell are integers starting from negative 2 … up to positive two.
Therefore, the allowed values of em sub ell are –2, -1, 0, +1 and +2
CLICK Therefore, the value that is not allowed is three.
Note that d orbitals always come in sets of five. The five orbitals in the set correspond to the five different em sub ell values.
The set of five 3d orbitals is called the 3d subshell, or the 3d sublevel.
In general, we can say that for a given value of ell, there are 2 ell plus one possible em sub ell values.
For ell equals zero,… two ell plus one equals one.
CLICK For ell equals one,… two ell plus one equals three.
For el equals two,… two ell plus one equals five.
What this means is that we can define an ess subshell as a set of consisting of only one orbital. We can say that ess orbitals come in sets of one.
We can define a pee subshell as a set of three orbitals. We can say that pee orbitals come in sets of three.
We can define a dee subshell as a set of five orbitals. We can say that dee orbitals come in sets of five.
And we can define an eff subshell as a set of seven orbitals. We can say that eff orbitals come in sets of seven.
END RECORDING
NOTE: d orbitals always come in sets of 5; these correspond to the five different ml values. The set of five 3d orbitals is called the 3d subshell, or 3d sublevel.

2. For a given l, there are (2l+1) possible ml values. For l=0: 2(0)+1 = 1
For l=0 (s subshell): orbital (ml = 0)
For l=1 (p subshell): orbitals (ml = -1, 0, +1)
For l=2 (d subshell): orbitals (ml = -2,-1, 0, +1, +2)
For l=3 (f subshell): orbitals (ml = -3, -2,-1, 0, +1, +2, +3)

3. Video ID: © 2008, Project VALUE (Video Assessment Library for Undergraduate Education), Department of Physical Sciences Nicholls State University Author: Glenn V. Lo Funded by Louisiana Board of Regents Contract No. LA-DL-SELECT-13-07/08