1. SCH12U September 13 2011 Mr. Dvorsky
Quantum Numbers
SCH12U
September
Mr. Dvorsky

2. Introduction to Quantum Numbers
The location of electrons can be identified by its orbital type. These names indicated the following about the electron:
Another system used to identify an electron is the quantum number system. With this system a particular electron is designated by a set of 4 numbers.

3. Principle Quantum Number,n
This indicates the energy level of the electron
i.e. N = 1,2,3,4,5, etc.
-can have any integer value between 1 and
infinity.

4. Secondary Quantum Number
Indicates the type of orbital that the electron is in.
l =0 (s orbital)
l = 1 (p orbital)
l = 2 (d orbital)
l = 3 (f orbital)

5. Magnetic Quantum Number, ml or m
This indicates the orientation of the orbital that the electron is in. The possible values depend on the value for l.
When l=0  ml = 0 (only 1 spherical orientation)
When l = 1  ml = +1 (px), ml = 0 (py), ml = -1 (pz)
When l = 2  ml = +2, +1, 0, -1, -2
When l = 3  ml = +3, +2, +1, 0, -1, -2, -3

6. Spin Quantum Number, ms or s
Each orbital can contain 2 electrons. However these 2 electrons must have opposite spin. These are the same for all orbitals.
ms = + ½ and - ½

7. n = 1 l = 0 ml = 0 n = 2 l = 1 ml = +1 n = 4 l = 2 ml = +2...0...-2
What are the possible quantum numbers of an electron in
the following orbitals:
a) 1s
b) 2px
c) 4d
Note that no 2 electrons in an atom can have the same 4
quantum numbers.
n = 1
l = 0
ml = 0
n = 2
l = 1
ml = +1
n = 4
l = 2
ml =