Chemistry 0871
Learning Centre
Atomic Structure:
Orbitals
Filling order for sublevels in relation to the periodic table:
1
2
He
1s
3
5
Li2s
11
7
10
N2p
Ne
13
3s
19
21
55
54
In
4d
Xe
5p
86
81
72
6s
5d
89
Kr
4p
49
Y
57
87
36
3d
39
5s
Ar
3p
31
4s
37
18
Aℓ
Rn
6p
104
118
113
7s
6d
Uuo
7p
71
58
4f
90
NOTATION
SUBLEVEL FILLING ORDER
1s22s22p3
principal
energy level
103
5f
1s22s22px12py12pz1
sublevel
orbital
electrons
in sublevel
Examples:
3 Li:
1s22s1
7 N:
1s22s22p3
13 Aℓ: [Ne]3s23p1
39 Y: [Kr] 5s24d1
49 In: [Kr] 5s24d105p1
© 2013 Vancouver Community College Learning Centre.
Student review only. May not be reproduced for classes.
1s
2s
2p
3s
3p
3d
4s
4p
4d
4f
5s
5p
5d
5f
5g
6s
6p
6d
6f
6g
7s
7p
7d
7f
7g
Authoredby
byEmily
Gordon
Wong
Simpson
MAXIMUM SUBLEVEL CAPACITY
Sublevel
s
p
d
f
Number of
Orbitals
1
3
5
7
Number of
Electrons
2
6
10
14
QUANTUM NUMBERS
Letter
Designation
Principal
Quantum
Number
(n)
Azimuthal
Quantum
Number (ℓ)
(subshell)
s p d f
…
0
0
1
0
1
2
Magnetic Quantum
Number
(m) −ℓ ≤ m ≤ ℓ
K
L
L
M
M
M
1
2
2
3
3
3
1s
0
2s
0
2p
−1, 0, +1
3s
0
3p
−1, 0, +1
3d −2, −1, 0, +1, +2
⋮
⋮
n 0 1 2 … n−1
Spin (s)
For each
orbital, one
electron has
s = +½,
the other has
s = −½.
IRREGULARITIES
Some irregularities occur within the periodic table (e.g., chromium and copper). These
elements do not follow the normal sublevel filling order. These irregularities can be
explained by applying the following rule:
A half-filled or completely-filled sublevel is more stable than an incompletelyfilled sublevel. Stable electron configurations are more likely than unstable ones.
Example: Chromium, atomic number 24.
INCOMPLETE
In normal order:
[Ar]
3d
4s
By the rule:
INCORRECT
FILLED
HALF-FILLED
HALF-FILLED
[Ar]
CORRECT
3d
4s
Example: Copper, atomic number 29.
INCOMPLETE
In normal order:
FILLED
[Ar]
3d
4s
By the rule:
FILLED
HALF-FILLED
[Ar]
INCORRECT
CORRECT
3d
4s
© 2013 Vancouver Community College Learning Centre.
Student review only. May not be reproduced for classes.
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