1. Quantum numbers and Periodic table
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2. What is an orbital?
It is the space around the nucleus in which the electron is found with a probability of 90%.
The electron spends 90% of its time in that space.
90%
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3. Different shapes of orbitals
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4. 2 1 3 Main shells sub- shells a b c d e f g a b g b g b g b g b g b g
university 1 2 3
Main
shells
Faculty of art
Faculty of
engineering
Faculty of science a b c d e f g
sub-
shells
Arabic
Engl.
Mech
civil
chem
phys
Math a b g b g b g b g b g b g D M B M B M B M B M B M B
Each student in the university is defined by a set of symbols:
A Math student in the master program has the set: 3 g b
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5. Similarly, electrons in atom are specified by a set of numbers, the quantum numbers:
name
symbol
values
Physical significance
Principal Quantum Number n
1, 2, 3, 4, …….
Gives the main shell in which the electron exists.
Determines largely the energy of the electron.
Determines the size of the orbital.
Azimuthal (secondary, angular moment) Quantum Number ℓ
0, 1, 2, …, (n-1)
-Gives the subshell in which the electron exists.
-contributes to energy of electron.
-Determines the shape of the orbital
Magnetic Quantum Number mℓ
-ℓ, …, 0, … +ℓ
-Determines the orientation of orbital in space
Spin Quantum Number ms
+/- 1/2
-orientation of rotation of electron around itself.
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6. Main shell designation
l-value
orbital type s 1 p 2 d 3 f 4 g 5 h
n-value
Main shell designation 1 K 2 L 3 M 4 N 5 O
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7. n mℓ 2n2 ℓ No. of orbitals No. of electrons (n-1) (-ℓ, …, +ℓ) 1 0 (s)2
1 (p)
-1, 0, 1 3 6 8
2 (d)
-2, 1, 0, 1, 2 5 10 18 4
3 (f)
-3, -2, 1, 0, 1, 2, 3 7 14 32
2n2
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10. Nodes: Regions where electrons are not allowed to be present in
Nodes: Regions where electrons are not allowed to be present in. Electron Probability of being there is zero.
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11. 3p 1 node II/ 3s: 3-0-1=2 nodes Number of nodes: n-ℓ-1
3d: 3-2-1=0 node
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