1. Electron Configuration
Filling-Order of Electrons in an Atom

2. 4f
Sublevels
4d
n=4
4p
3d
4s
Energy n=3 3p
3s
2p
n=2
2s
n=1 1s

3. 4f
Sublevels
4d
s p d f n=4
s p d
4p
s p
s 3d
4s
Energy
n=3 3p
3s
1s22s22p63s23p64s23d104p65s24d10…
2p
n=2
2s
n=1 1s

4. Filling Rules for Electron Orbitals
Aufbau Principle: Electrons are
added one at a time to the lowest
energy orbitals available until all the
electrons of the atom have been
accounted for.
*Aufbau is German for “building up”

5. Energy Level Diagram
6s 6p 5d 4f
5s 5p 4d
Bohr Model
4s 4p 3d
Arbitrary Energy Scale
3s 3p
N
2s 2p
1s
Electron Configuration
NUCLEUS
H He Li C N Al Ar F Fe La
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6. Energy Level Diagram
6s 6p 5d 4f Hydrogen
5s 5p 4d
Bohr Model
4s 4p 3d
Arbitrary Energy Scale
3s 3p
N
2s 2p
1s
Electron Configuration
NUCLEUS
H = 1s1
H He Li C N Al Ar F Fe La
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7. Energy Level Diagram
6s 6p 5d 4f Helium
5s 5p 4d
Bohr Model
4s 4p 3d
Arbitrary Energy Scale
3s 3p
N
2s 2p
1s
Electron Configuration
NUCLEUS
He = 1s2
H He Li C N Al Ar F Fe La
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8. Energy Level Diagram
6s 6p 5d 4f Lithium
5s 5p 4d
Bohr Model
4s 4p 3d
Arbitrary Energy Scale
3s 3p
N
2s 2p
1s
Electron Configuration
NUCLEUS
Li = 1s22s1
H He Li C N Al Ar F Fe La
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9. Energy Level Diagram
6s 6p 5d 4f Carbon
5s 5p 4d
Bohr Model
4s 4p 3d
Arbitrary Energy Scale
3s 3p
N
2s 2p
1s
Electron Configuration
NUCLEUS
C = 1s22s22p2
H He Li C N Al Ar F Fe La
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10. Energy Level Diagram
6s 6p 5d 4f Nitrogen
5s 5p 4d
Bohr Model
4s 4p 3d
Arbitrary Energy Scale
3s 3p
N
Hund’s Rule “maximum
number of unpaired
orbitals”.
2s 2p
1s
Electron Configuration
NUCLEUS
N = 1s22s22p3
H He Li C N Al Ar F Fe La
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11. Energy Level Diagram
6s 6p 5d 4f Fluorine
5s 5p 4d
Bohr Model
4s 4p 3d
Arbitrary Energy Scale
3s 3p
N
2s 2p
1s
Electron Configuration
NUCLEUS
F = 1s22s22p5
H He Li C N Al Ar F Fe La
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12. Energy Level Diagram
6s 6p 5d 4f Aluminum
5s 5p 4d
Bohr Model
4s 4p 3d
Arbitrary Energy Scale
3s 3p
N
2s 2p
1s
Electron Configuration
NUCLEUS
Al = 1s22s22p63s23p1
H He Li C N Al Ar F Fe La
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13. Energy Level Diagram
6s 6p 5d 4f Argon
5s 5p 4d
Bohr Model
4s 4p 3d
Arbitrary Energy Scale
3s 3p
N
2s 2p
1s
Electron Configuration
NUCLEUS
Ar = 1s22s22p63s23p6
H He Li C N Al Ar F Fe La
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14. Energy Level Diagram
6s 6p 5d 4f Iron
5s 5p 4d
Bohr Model
4s 4p 3d
Arbitrary Energy Scale
3s 3p
N
2s 2p
1s
Electron Configuration
NUCLEUS
Fe = 1s22s22p63s23p64s23d6
H He Li C N Al Ar F Fe La
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15. Energy Level Diagram
6s 6p 5d 4f Lanthanum
5s 5p 4d
Bohr Model
4s 4p 3d
Arbitrary Energy Scale
3s 3p
N
2s 2p
1s
Electron Configuration
NUCLEUS
La = 1s22s22p63s23p64s23d10
H He Li C N Al Ar F Fe La 4p65s24d105p66s25d1
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16. Write out the complete electron configuration for the following:
1) An atom of nitrogen
2) An atom of silver
POP
3) An atom of krypton
QUIZ
Draw a Bohr model an Argon atom .

17. Answer Key
Write out the complete electron configuration for the following:
1) An atom of nitrogen 1s22s22p3
2) An atom of silver 1s22s22p63s23p64s23d104p65s24d9
3) An atom of krypton 1s22s22p63s23p64s23d104p6
Draw a Bohr model of a Argon atom.
n=
n
22+

18. Periodic Table – Filling Order

19. Electron Configurations and
the Periodic Table

20. Orbitals Being Filled
1 Groups 8
1 1s 2 3 4 5 6 7 1s
2 2s 2p
3 3s 3p
Periods
4 4s 3d 4p
5 5s 4d 5p
6 6s La 5d 6p
7 7s Ac 6d
4f Lanthanide series
5f Actinide series

21. Electron Filling in Periodic Table s
s
1 p
2
3 d
4
5
6 ∗
7 Ω
f
∗
Ω

22. s
s
H He
H p 1 2
1
1
Li Be B C N O F Ne
2
3 4 5 6 7 8 9 10
Na Mg d Al Si P S Cl Ar
3
11 12 13 14 15 16 17 18
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
4
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe
5
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
Cs Ba Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
6 ∗
55 56 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
Fr Ra Rf Db Sg Bh Hs Mt
7 Ω
87 88 104 105 106 107 108 109
f
La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
∗
57 58 59 60 61 62 63 64 65 66 67 68 69 70 71
Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr
Ω
89 90 91 92 93 94 95 96 97 98 99 100 101 102 103

23. Electron Filling in Periodic Table s
s
H He
H p 1s1 1s2
1
1s1
Li Be B C N O F Ne
2
2s1 2s2 2p1 2p2 2p3 2p4 2p5 2p6
Na Mg d Al Si P S Cl Ar
3
3s1 3s2 3p1 3p2 3p3 3p4 3p5 3p6
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
4
4s1 4s2 3d1 3d2 3d3 3d5 3d5 3d6 3d7 3d8 3d10 3d10 4p1 4p2 4p3 4p4 4p5 4p6
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe
5
5s1 5s2 4d1 4d2 4d4 4d5 4d6 4d7 4d8 4d10 4d10 4p1 5p1 5p2 5p3 5p4 5p5 5p6
Cs Ba Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
6 ∗
6s1 6s2 5d2 5d3 5d4 5d5 5d6 5d7 5d9 5d10 5d10 6p1 6p2 6p3 6p4 6p5 6p6
Fr Ra H H H H H H
7 Ω
7s1 7s2 1s1 1s1 1s1 1s1 1s1 1s1
f
La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
∗
5d1 4f2 4f3 4f4 4f5 4f6 4f7 4f7 4f9 4f10 4f11 4f12 4f13 4f14 4f114
Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr
Ω
6d1 6d2 5f2 5f3 5f4 5f6 5f7 5f7 5f8 5f10 5f11 5f14 5f13 5f14 5f14