Lecture 3
September 14, 2009

Periodic Table Quiz
1
3 4
11 12
5
13
6
14
7
15
8
16
9
17
2
10
18
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
55 56 57 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
87 88 89
Name Grade /10
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La Lazy
Ce college
Pr professors
Nd never
Pm produce
Sm sufficiently
Eu educated
Gd graduates
Tb to
Dy dramatically
Ho help
Er executives
Tm trim
Yb yearly
Lu losses.
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La Loony
Ce chemistry
Pr professor
Nd needs
Pm partner:
Sm seeking
Eu educated
Gd graduate cannot be referring to 3.091!
Tb to
Dy develop
Ho hazardous
Er experiments
Tm testing
Yb young
Lu lab assistants.
must be the “other” chemistry professor
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CEase not I to slave, back breaking to tend;
PRideless and bootless stoking hearth and fire.
No Dream of mine own precious time to spend
Pour'ed More to sate your glutt'nous desire.
SMelting anew my ten-thousandth hour
EUtopia forever I eschew.
Growing Dimmer is my fleeing power
To Bid these curs'ed problem sets adieu.
DYing away whilst thy hosts are fought
HOpeless I come should in lecture I doze.
ERgo, like a sad slave, stay and rest nought.
Then Must I tool and toil while fatigue grows.
Yet, Bloody though I must be, and quite ill
Light the Universal abyss I will.
Courtesy of MIT Student. Used with permission.
57
138.9055
920
3455
6.146
1.10
5.577
[Xe]5d 1 6s 2
Lanthanum
*
57
3
La

status report ca . end of the 19th century
* atom is electrically neutral
* -ve charge carried by electrons
* e has very small mass
 bulk of the atom is +ve,
 most mass resides in +ve charge
Question: what is the spatial distribution of charge inside an atom?

Figure 1.18
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Figure 1.19
10-cm lead 0.5- cm lead Paper
γ rays
β particles
α particles
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Rutherford-Geiger-Marsden experiment
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Marsden's Analysis
Trajectory of incident
α particle b q gold nucleus
Scattering of an α -particle which approaches a heavy nucleus with an impact parameter b.
Image by MIT OpenCourseWare.

principles of modern chemistry:
*
*

Bohr Postulates for the Hydrogen Atom
1. Rutherford atom is correct
2. Classical EM theory not applicable to orbiting e -
3. Newtonian mechanics applicable to orbiting e -
4. E electron
= E kinetic
+ E potential
5. e energy quantized through its angular momentum:
L = mvr = nh /2 π , n = 1, 2, 3,…
6. Planck-Einstein relation applies to e transitions:
Δ E = E f
- E i
= h ν = hc / λ c = νλ

Bohr Postulates for the Hydrogen Atom
1. Rutherford atom is correct
2. Classical EM theory not applicable to orbiting e -
3. Newtonian mechanics applicable to orbiting e -
4. E electron
= E kinetic
+ E potential
5. e energy quantized through its angular momentum:
L = mvr = nh /2 π , n = 1, 2, 3,…
6. Planck-Einstein relation applies to e transitions:
Δ E = E f
- E i
= h ν = hc / λ c = νλ

Image by MIT OpenCourseWare.

Bohr Postulates for the Hydrogen Atom
1. Rutherford atom is correct
2. Classical EM theory not applicable to orbiting e -
3. Newtonian mechanics applicable to orbiting e -
4. E electron
= E kinetic
+ E potential
5. e energy quantized through its angular momentum:
L = mvr = nh /2 π , n = 1, 2, 3,…
6. Planck-Einstein relation applies to e transitions:
Δ E = E f
- E i
= h ν = hc / λ c = νλ

Bohr Postulates for the Hydrogen Atom
1. Rutherford atom is correct
2. Classical EM theory not applicable to orbiting e -
3. Newtonian mechanics applicable to orbiting e -
4. E electron
= E kinetic
+ E potential
5. e energy quantized through its angular momentum:
L = mvr = nh /2 π , n = 1, 2, 3,…
6. Planck-Einstein relation applies to e transitions:
Δ E = E f
- E i
= h ν = hc / λ c = νλ

0
UV Visible
6000 K
Infrared
Planck suggests that light is composed of energy packets or quanta. The elementary unit of e-m radiation is the photon .
5000 K
Classical prediction
6000 K
E = h ν
500
4000 K
3000 K
1000 1500
Wavelength (nm)
2000 2500 3000
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Bohr Postulates for the Hydrogen Atom
1. Rutherford atom is correct
2. Classical EM theory not applicable to orbiting e -
3. Newtonian mechanics applicable to orbiting e -
4. E electron
= E kinetic
+ E potential
5. e energy quantized through its angular momentum:
L = mvr = nh /2 π , n = 1, 2, 3,…
6. Planck-Einstein relation applies to e transitions:
Δ E = E f
- E i
= h ν = hc / λ c = νλ

Image by MIT OpenCourseWare.

© source unknown. All rights reserved. This image is excluded from our Creative Commons license.For more information, see http://ocw.mit.edu/fairuse .

© source unknown. All rights reserved. This image is excluded from our Creative
Commons license. For more information, see http://ocw.mit.edu/fairuse .

© source unknown. All rights reserved. This image is excluded from our
Creative Commons license. For more information, see http://ocw.mit.edu/fairuse .

© source unknown. All rights reserved. This image is excluded from our
Creative Commons license. For more information, see http://ocw.mit.edu/fairuse .

© source unknown. All rights reserved. This image is excluded from our
Creative Commons license. For more information, see http://ocw.mit.edu/fairuse .

1803 1904 1911
Dalton proposes the indivisible unit of an element is the atom.
1913
Thomson discovers electrons, believed to reside within a sphere of uniform positive charge (the "plum pudding" model).
1926
Rutherford demonstrates the existence of a positively charged nucleus that contains nearly all the mass of an atom.
Bohr proposes fixed circular orbits around the nucleus for electrons.
In the current model of the atom, electrons occupy regions of space (orbitals) around the nucleus determined by their energies.
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J. J. Thomson (1856-1940)
Cathode ray = Charged particle = Electron (1897) charge-to-mass ratio of electron (1897)
Henri Becquerel (1852-1908)
Uranium emits rays that fog photographic film (1869)
Robert Millikan
(1868-1953)
Charge and mass of electron
(1909)
J.J Thomson
"Plum pudding" model of atom (1904)
Marie and Pierre Curie
(1867-1934, 1854-1906)
Radioactive elements polonium and radium (1898)
Ernest Rutherford
(1871-1937)
α and β particles (1898)
Ernest Rutherford
Nuclear model of atom (1911)
Ernest Rutherford
Proton (1920)
James Chadwick
(1891-1974)
Neutron (1932)
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3.091SC Introduction to Solid State Chemistry
Fall 2009
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