Atomic Structure
Quantum Numbers
Quantum Numbers
 specify
the properties of orbitals and
of electrons in orbitals
 the first three numbers describe:



main energy level (n)
Shape (l)
Orientation (ml)
 4th
describes spin of electron (ms)
1st Quantum Number (n)
 main
energy level occupied by electron
 values are all positive whole # integers
(1,2,3,…)
 As it increases, the electron:


has more energy
is farther from nucleus
 the
total number of orbitals in a level
is equal to n2
1st Quantum Number (n)
n
1
2
3
4
# of orbitals
1
4
9
16
nd
2
Quantum Number (l)
 the
shape of the orbital (sublevel)
 # possible shapes = energy level

4th energy level has 4 possible shapes
 possible




s: 0
p: 1
d: 2
f: 3
values: 0 to n-1
2nd Quantum Number
Level
Sublevels
Sublevels
0
1
2
0
1
2
0
1
0
3
3rd Quantum Number (ml)
 the
position of an orbital around the
nucleus (x, y, or z direction)
 has values from +l  -l
 each orbital holds maximum of 2
electrons
4th Quantum Number (ms)
 the
spin state of the electron
 only 2 possible directions
 only 2 possible values: +½ and -½
 paired electrons must
have opposite spins
-1/2
+1/2
Connection to Configurations
1.
2.
3.
Draw out the orbital notation for the
last sublevel filled in an atom
Circle the last electron inserted in
that sublevel
Find the four quantum numbers for
that electron
Example 1
What are the 4 quantum numbers for
the electron of highest energy in
nitrogen?
Example 2
What are the 4 quantum numbers for
the electron of highest energy in
sulfur?
Example 2
What are the 4 quantum numbers for
the electron of highest energy in
iron?
Example 4
What are the 4 quantum numbers for
the electron of highest energy in
calcium?