Hoa dai cuong_chuong 7

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General Chemistry: Chapter 9
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Philip Dutton
University of Windsor, Canada

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General Chemistry
Principles and Modern Applications
Petrucci • Harwood • Herring
8th Edition
Chapter 9: Electrons in Atoms
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General Chemistry: Chapter 9
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Contents
9-1 Electromagnetic Radiation
9-2 Atomic Spectra
9-3 Quantum Theory
9-4 The Bohr Atom
9-5 Two Ideas Leading to a New Quantum Mechanics
9-6 Wave Mechanics
9-7 Quantum Numbers and Electron Orbitals


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Contents
9-8 Quantum Numbers
9-9 Interpreting and Representing Orbitals of the Hydrogen Atom
9-9 Electron Spin
9-10 Multi-electron Atoms
9-11 Electron Configurations
9-12 Electron Configurations and the Periodic Table
Focus on Helium-Neon Lasers

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9-1 Electromagnetic Radiation
Electric and magnetic fields propagate as waves through empty space or through a medium.
A wave transmits energy.
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EM Radiation
Low 
High 
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Frequency, Wavelength and Velocity
Frequency () in Hertz—Hz or s-1.
Wavelength (λ) in meters—m.
cm m nm  pm
(10-2 m) (10-6 m) (10-9 m) (10-10 m) (10-12 m)

Velocity (c)—2.997925  108 m s-1.

c = λ λ = c/ = c/λ
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Electromagnetic Spectrum
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Red
Orange
Yellow
Green
Blue
Indigo
Violet
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ROYGBIV
700 nm
450 nm
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Constructive and Destructive Interference
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Refraction of Light
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9-2 Atomic Spectra
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Atomic Spectra
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9-3 Quantum Theory
Blackbody Radiation:
Max Planck, 1900:
Energy, like matter, is discontinuous.
є = h
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The Photoelectric Effect
Light striking the surface of certain metals causes ejection of electrons.

 > o threshold frequency
e-  I
ek  
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The Photoelectric Effect
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The Photoelectric Effect
At the stopping voltage the kinetic energy of the ejected electron has been converted to potential.
mu2 = eVs
1
2
At frequencies greater than o:
Vs = k ( - o)
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The Photoelectric Effect
Eo = ho
Ek = eVs
o =
eVo
h
eVo, and therefore o, are characteristic of the metal.
Conservation of energy requires that:
h =
mu2 + eVo
2
1
mu2 = h - eVo
eVs =
2
1
Ephoton = Ek + Ebinding
Ek = Ephoton - Ebinding
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9-4 The Bohr Atom
RH = 2.179  10-18 J
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Energy-Level Diagram
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Ionization Energy of Hydrogen
ΔE = RH (
ni2
1
nf2
–
1
) = h
As nf goes to infinity for hydrogen starting in the ground state:
This also works for hydrogen-like species such as He+ and Li2+.
h = -Z2 RH
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Emission and Absorption Spectroscopy
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9-5 Two Ideas Leading to a New Quantum Mechanics
Wave-Particle Duality.
Einstein suggested particle-like properties of light could explain the photoelectric effect.
But diffraction patterns suggest photons are wave-like.
deBroglie, 1924
Small particles of matter may at times display wavelike properties.
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deBroglie and Matter Waves
E = mc2
h = mc2
h/c = mc = p
p = h/λ

λ = h/p = h/mu
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X-Ray Diffraction
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The Uncertainty Principle
Δx Δp ≥
h
4π
Werner Heisenberg
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9-6 Wave Mechanics
Standing waves.
Nodes do not undergo displacement.


λ = , n = 1, 2, 3…
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Wave Functions
ψ, psi, the wave function.
Should correspond to a standing wave within the boundary of the system being described.
Particle in a box.

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Probability of Finding an Electron
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Wave Functions for Hydrogen
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Principle Shells and Subshells
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Orbital Energies
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9-8 Interpreting and Representing the Orbitals of the Hydrogen Atom.
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s orbitals
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p Orbitals
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p Orbitals
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d Orbitals
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9-9 Electron Spin: A Fourth Quantum Number
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9-10 Multi-electron Atoms
Schrödinger equation was for only one e-.
Electron-electron repulsion in multi-electron atoms.
Hydrogen-like orbitals (by approximation).

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Penetration and Shielding
Zeff is the effective nuclear charge.
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9-11 Electron Configurations
Aufbau process.
Build up and minimize energy.
Pauli exclusion principle.
No two electrons can have all four quantum numbers alike.
Hund’s rule.
Degenerate orbitals are occupied singly first.
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Orbital Energies
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Orbital Filling
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Aufbau Process and Hunds Rule
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Filling p Orbitals
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Filling the d Orbitals
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Electon Configurations of Some Groups of Elements
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9-12 Electron Configurations and the Periodic Table
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Focus on He-Ne Lasers
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General Chemistry: Chapter 9
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Chapter 9 Questions
1, 2, 3, 4, 12, 15, 17, 19, 22, 25, 34, 35, 41, 67, 69, 71, 83, 85, 93, 98