1. III. Quantum Model of the Atom (p. 129-134)
Ch. 5 - Electrons in Atoms
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2. A. Electrons as Waves Louis de Broglie (1924)
Applied wave-particle theory to e-
e- exhibit wave properties
QUANTIZED WAVELENGTHS
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3. A. Electrons as Waves
QUANTIZED WAVELENGTHS
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4. A. Electrons as Waves EVIDENCE: DIFFRACTION PATTERNS VISIBLE LIGHT
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5. B. Quantum Mechanics Heisenberg Uncertainty Principle
Impossible to know both the velocity and position of an electron at the same time
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6. B. Quantum Mechanics Schrödinger Wave Equation (1926)
finite # of solutions  quantized energy levels
defines probability of finding an e-
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7. Radial Distribution Curve
B. Quantum Mechanics
Orbital (“electron cloud”)
Region in space where there is 90% probability of finding an e-
Orbital
Radial Distribution Curve
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8. C. Quantum Numbers Four Quantum Numbers:
Specify the “address” of each electron in an atom
UPPER LEVEL
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9. C. Quantum Numbers 1. Principal Quantum Number ( n ) Energy level
Size of the orbital
n2 = # of orbitals in the energy level
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10. C. Quantum Numbers f d s p 2. Angular Momentum Quantum # ( l )
Energy sublevel
Shape of the orbital f d s p
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11. C. Quantum Numbers n = # of sublevels per level
n2 = # of orbitals per level
Sublevel sets: 1 s, 3 p, 5 d, 7 f
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12. C. Quantum Numbers 3. Magnetic Quantum Number ( ml )
Orientation of orbital
Specifies the exact orbital within each sublevel
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13. C. Quantum Numbers px py pz
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14. C. Quantum Numbers 2s 2px 2py 2pz
Orbitals combine to form a spherical shape. 2s
2pz
2py
2px
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16. C. Quantum Numbers 4. Spin Quantum Number ( ms )
Electron spin  +½ or -½
Draw them as “up” or “down”
An orbital can hold 2 electrons that spin in opposite directions.
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17. C. Quantum Numbers Pauli Exclusion Principle
No two electrons in an atom can have the same 4 quantum numbers.
Each e- has a unique “address”:
1. Principal # 
2. Ang. Mom. # 
3. Magnetic # 
4. Spin # 
energy level
sublevel (s,p,d,f)
orbital
Electron (up or down)
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18. Number of Atomic Orbitals Total Number of orbitals
Energy level
Sublevels
Number of Atomic Orbitals
Total Number of orbitals 1 s 2 p 3 4 d 5 9 f 7 16
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19. Feeling overwhelmed?
Read Chapter 5!
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