General Chemistry
Principles and Modern Applications
Petrucci • Harwood • Herring
8th Edition
Chapter 9: Electrons in Atoms
Philip Dutton
University of Windsor, Canada
Prentice-Hall © 2002
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 1 of 50
Contents
9-1
9-2
9-3
9-4
9-5
9-6
9-7
Electromagnetic Radiation
Atomic Spectra
Quantum Theory
The Bohr Atom
Two Ideas Leading to a New Quantum Mechanics
Wave Mechanics
Quantum Numbers and Electron Orbitals
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 2 of 50
Contents
9-8
9-9
Quantum Numbers
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
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 3 of 50
9-1 Electromagnetic Radiation
• Electric and magnetic fields
propagate as waves through
empty space or through a
medium.
• A wave transmits energy.
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 4 of 50
EM Radiation
Low 
High 
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 5 of 50
Frequency, Wavelength and Velocity
• Frequency () in Hertz—Hz or s-1.
• Wavelength (λ) in meters—m.
• cm
m
nm

(10-2 m)
(10-6 m) (10-9 m)
pm
(10-10 m) (10-12 m)
• Velocity (c)—2.997925  108 m s-1.
c = λ
Prentice-Hall © 2002
λ = c/
General Chemistry: Chapter 9
= c/λ
Slide 6 of 50
Electromagnetic Spectrum
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 7 of 50
ROYGBIV
Red
Orange
Yellow
700 nm
450 nm
Green
Blue
Indigo
Violet
© 2002
Prentice-Hall ©2002
General
GeneralChemistry:
Chemistry: Chapter
Chapter99
Slide 8 of 50
Constructive and Destructive Interference
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 9 of 50
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 10 of 50
Refraction of Light
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 11 of 50
9-2 Atomic Spectra
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 12 of 50
Atomic Spectra
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 13 of 50
9-3 Quantum Theory
Blackbody Radiation:
Max Planck, 1900:
Energy, like matter, is discontinuous.
є = h
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 14 of 50
The Photoelectric Effect
• Light striking the surface of certain metals
causes ejection of electrons.
•  > o
• e-  I
• ek  
Prentice-Hall © 2002
threshold frequency
General Chemistry: Chapter 9
Slide 15 of 50
The Photoelectric Effect
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 16 of 50
The Photoelectric Effect
• At the stopping voltage the kinetic energy of the
ejected electron has been converted to potential.
1
mu2 = eVs
2
• At frequencies greater than o:
Vs = k ( - o)
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 17 of 50
The Photoelectric Effect
Ek = eVs
Eo = ho
eVo
o =
h
eVo, and therefore o, are characteristic of the metal.
Conservation of energy requires that:
Ephoton = Ek + Ebinding
Ek = Ephoton - Ebinding
Prentice-Hall © 2002
1
mu2 + eVo
h =
2
1
eVs =
mu2 = h - eVo
2
General Chemistry: Chapter 9
Slide 18 of 50
9-4 The Bohr Atom
-RH
E= 2
n
RH = 2.179  10-18 J
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 19 of 50
Energy-Level Diagram
-RH -RH
– 2
ΔE = Ef – Ei =
2
nf
ni
1
1
–
= RH ( 2
) = h = hc/λ
2
ni
nf
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 20 of 50
Ionization Energy of Hydrogen
1
1
–
ΔE = RH ( 2
) = h
2
ni
nf
As nf goes to infinity for hydrogen starting in the ground state:
1
h = RH ( 2 ) = RH
ni
This also works for hydrogen-like species such as He+ and Li2+.
h = -Z2 RH
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 21 of 50
Emission and Absorption Spectroscopy
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 22 of 50
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.
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 23 of 50
deBroglie and Matter Waves
E = mc2
h = mc2
h/c = mc = p
p = h/λ
λ = h/p = h/mu
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 24 of 50
X-Ray Diffraction
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 25 of 50
The Uncertainty Principle
• Werner Heisenberg
h
Δx Δp ≥
4π
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 26 of 50
9-6 Wave Mechanics
• Standing waves.
– Nodes do not undergo displacement.
2L
λ=
, n = 1, 2, 3…
n
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 27 of 50
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.
ψ 
Prentice-Hall © 2002
General Chemistry: Chapter 9
2
 n x 
sin 

L
 L 
Slide 28 of 50
Probability of Finding an Electron
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 29 of 50
Wave Functions for Hydrogen
• Schrödinger, 1927
Eψ = H ψ
– H (x,y,z) or H (r,θ,φ)
ψ(r,θ,φ) = R(r) Y(θ,φ)
R(r) is the radial wave function.
Y(θ,φ) is the angular wave function.
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 30 of 50
Principle Shells and Subshells
• Principle electronic shell, n = 1, 2, 3…
• Angular momentum quantum number,
l = 0, 1, 2…(n-1)
l = 0, s
l = 1, p
l = 2, d
l = 3, f
Prentice-Hall © 2002
• Magnetic quantum number,
ml= - l …-2, -1, 0, 1, 2…+l
General Chemistry: Chapter 9
Slide 31 of 50
Orbital Energies
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 32 of 50
9-8 Interpreting and Representing the
Orbitals of the Hydrogen Atom.
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 33 of 50
s orbitals
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 34 of 50
p Orbitals
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 35 of 50
p Orbitals
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 36 of 50
d Orbitals
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 37 of 50
9-9 Electron Spin: A Fourth Quantum
Number
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 38 of 50
9-10 Multi-electron Atoms
• Schrödinger equation was for only one e-.
• Electron-electron repulsion in multielectron atoms.
• Hydrogen-like orbitals (by approximation).
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 39 of 50
Penetration and Shielding
Zeff is the effective nuclear charge.
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 40 of 50
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.
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 41 of 50
Orbital Energies
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 42 of 50
Orbital Filling
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 43 of 50
Aufbau Process and Hunds Rule
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 44 of 50
Filling p Orbitals
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 45 of 50
Filling the d Orbitals
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 46 of 50
Electon Configurations of Some Groups of
Elements
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 47 of 50
9-12 Electron Configurations and the Periodic Table
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 48 of 50
Focus on He-Ne Lasers
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 49 of 50
Chapter 9 Questions
1, 2, 3, 4, 12, 15,
17, 19, 22, 25, 34,
35, 41, 67, 69, 71,
83, 85, 93, 98
Prentice-Hall © 2002
General Chemistry: Chapter 9
Slide 50 of 50