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1. QUANTUM NUMBER
Edited by → Waseem Ahmed Bhatti (M.Sc Chemistry)
Email address → waseembhatti854@gmail.com
Contact No → 0302-3095007 --- 0314-7732937

2. Quantum Number
▪ Principal Quantum Number → denoted by (n)
▪ Azimuthal Quantum Number → denoted by (l)
▪ Magnetic Quantum Number → denoted by (ml)
▪ Spin Quantum Number → denoted by (ms)
We used these parameter for identity and location of electrons or
address of electrons.

3. Principal Quantum Number (n)
- Distance from nucleus (Size)
- Energy of an electron
n → 1,2,3,4,5 ……. so on
The value of principal quantum positive integer
↓ ↓ ↓ ↓ ↓
This principal quantum number given information about shell of an
atom.

4. Subshells
Same n → Same shell
Subshell Shape
▪ s ▪ Spherical
▪ p ▪ collection of dumb-bell
▪ d ▪ collection of double dumb-bell
▪ F ▪ ---------------------------------

5. Azimuthal Quantum Number (l)
• s • l = 0 • n = 1 • 1s0
• p • l = 1 • n = 2 • 2s0 2p1
• d • l = 2 • n = 3 • 3s0 3p1 3d2
• f • l = 3 • n = 4 • 4s0 4p1 4d2 4f3
l = 0 - n = 1
l = 1 - n = 2
l = 2 - n = 3
l = 3 - n = 4
→ Shape
→ Energy

6. Orbitals & Orientation
➢ p Orbitals
• x-axis oriented
• y-axis oriented →
• Z-axis oriented
➢ d Orbital
• xy-axis oriented
• xz-axis oriented
• yz-axis oriented →
• x2 – y2 - axis oriented
• z2 – axis oriented

7. Magnetic Quantum Number (m)
• l • Subshell • Orientation • ml
• 0 • s n = 1 • 1 • 0
• 1 • p n = 2 • 3 (px py pz) • -1, 0, +1
• 2 • d n = 3 • 5 (dxy dxz dyz dx2-y2 dz2) • -2, -1, 0, +1, +2
• 3 • f n = 4 • ----------------------------------- • -3, -2, -1, 0, +1, +2, +3
ml → -l, 0, +l

8. Degenerate Orbitals
3px
3py
3pz
→ n = 3
→ l = 1
5dxy
5dxz
5dyz
5dx2-y2
5dz2
→ n = 5
→ l = 2
n,l identical
Energy identical

9. Spin Quantum Number (ms)
Each orbital can accommodate maximum of 2
electrons
• Opposite spins ms
• ↻ +½ clockwise
• ↺ -½ anti clockwise