Modern Atomic Theory and the Periodic Table

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Modern Atomic Theory and the Periodic Table
Preparation for College Chemistry Luis
Avila Columbia University Department of Chemistry
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mgrafite 9.8266kg
e.m.f .992 V
Nature is Continuous
e.m.f 1.0 V
mgrafite 9.83kg
Classical Mechanics Central Ideas
E
V
Total Energy of a Particle in Motion
As a function of momentum p
Trajectory Statement of both p(t) and x(t) of a
particle
Knowing the forces among particles it is possible
to predict the future trajectory of a group of
particles
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Thomson discovers the electron
Plancks Quantum Theory (Max Planck)
Einsteins Photons
Rutherford Experiment
Bohrs atomic Model (Niels Bohr)
De Broglie Waves (Louis De Broglie)
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Quantum Mechanics (Heisenberg, Max Born)
The Wave equation (Erwin Schrödinger)
Indeterminacy Principle (W. Heisemberg)
Copenhagen Interpretation (Bohr, Heisemberg,
Schrödinger)
Complementarity Principle Knowledge of atomic
and molecular-scale phenomena is essentially
incomplete until both particle and wave aspects
of it are known.
Robert Oppenheimer
Paul Dirac
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Failures of Classical Mechanics
Atoms are discrete
e 1.6021773 x 10-19 C
2000 K
M12-C 1.99265 x 10-26 kg
Visible region
1750 K
1250 K
Black-body Radiation
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Ultraviolet Catastrophe
Raileigh-Jean
Observed, Planck
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Photoelectric Effect
? lt ?0
? ?0
e-
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The Work Function
E
?
?
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Characteristics of a Wave
Wavelength
Amplitude
Wavelength
High frequency wave
t(s)
Low frequency wave
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Characteristics of a Wave
Progress of a cycle Phase
90
180
360
0
270
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Characteristics of a Wave
Orientation Polarization
Electric Field
Magnetic Field
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Wave Interference
Out of Phase
Destructive Interference


In Phase
Constructive Interference
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Atomic (line) Spectra
2nd excited state
1st excited state
Ground state
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Planck Equation. Max Plank 1900
EM radiation is emitted in QUANTA with energy E
Planck-Einstein Equation
h Planck Constant 6.621 x 10-34 Js
c Speed of light in vacuum 2.99 108 ms-1
Ex. The energy for the yellow line in the sodium
spectrum with a l 589 nm
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Atomic models
Rutherford- Circular ORBITS
Bohr -Circular Quantized ORBITS
Bohr- Sommerfeld Circular and elliptical
Quantized ORBITS
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The Bohr-Sommerfeld Atom
Circular Quantized ORBITS
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The Quantum Mechanical Atom
Erwin Schrödinger 1925- Wave equation
Werner Heisenberg 1927
http//www.aip.org/history/heisenberg/
Uncertainty (Indeterminacy) Principle
?x l ?p h/ l
Probabilistic Region ORBITAL
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Four Quantum Numbers
n Principal Quantum number (orbital size,
energy, shells)
l Secondary Quantum number (orbital shape)
ml Magnetic Quantum number (orbital
orientation in space)
ms (s) Spin Quantum number (orbital energy)
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Sublevels
Quantum number l takes on values 0, 1, 2,
...(n-1) according to values of n
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2
3
1
n
l
0
0, 1
0, 1, 2
0, 1, 2, 3
s, p, d, f
s, p
s
s, p, d
Orbitals
l 0 (s) l 1 (p) l 2 (d) l 3(f)
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Sublevels
Magnetic Quantum number ml takes on values
-l,...,0,...l It divides the sublevels into
individual orbitals.
1
2
l
0
ml
-1, 0, 1
0
-2, -1, 0, 1, 2
s
px , py , pz
dxz , dxy ,, dyz , dz2 , dx2- z2
Orbitals
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Pauli Exclusion Principle
No two electrons in an orbital may have the same
set of quantum numbers, or two electrons with the
same spin may not occupy the same point in space
at the same time
Maximum capacity of principal level 2n2
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Energy Levels of Electrons
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18
8
2
Maximum capacity of principal level 2n2
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Arrangement of electrons in orbitalsAufbau
(building up) principle

• Electronic Configuration

3d6
nl electrons

• Orbital diagram

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Orbital Filling
Z
Element
Electronic config.
1s
2s
2p
1
H
1s1
He
2
1s2
Li
He2s1
3
Be
He2s2
4
B
He2s2 2p1
5
6
C
He2s2 2p2
7
N
He2s2 2p3
8
He2s2 2p4
O
9
He2s2 2p5
F
10
He2s2 2p6
Ne
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Orbital Filling
Z
Element
Electronic config.
3s
3p
11
Na
Ne3s1
Mg
12
Ne3s2
Al
Ne3s2 3p1
13
Si
Ne3s2 3p2
14
P
15
Ne3s2 3p3
16
S
Ne3s2 3p4
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Cl
Ne3s2 3p5
Ar
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Ne3s2 3p6
Hunds Rule
When e- are added to equal energy orbitals. They
will half fill every orbital before pairing
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Sublevels of Increasing Energy
4f
Energy
4d
4
4p
3d
4s
3
3p
3s
2p
2
2s
1
1s
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n l rule
1. The electron will occupy the orbital
with the smaller n l value
2. When two orbitals have the same n l
value, the electron will occupy the
orbital with smaller n.
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Periodic Chart
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
47
37
38
39
40
41
42
43
44
45
46
48
49
50
51
52
53
54
55
56
57
72
73
74
75
76
77
78
79
80
8l
82
83
84
85
86
87
88
89
104
105
106
107
108
109
58
59
60
61
62
63
64
65
66
67
68
69
70
71
90
91
92
93
94
95
96
97
98
99
100
101
102
103
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s-block
Group 1 Alkali Metals (ns1)
Group 2 Alkali-Earth Metals (ns2)
H
He
Be
Li
Mg
Na
Ca
K
Sr
Rb
Ba
Cs
Ra
Fr
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VIIIA Noble Gases, ns2p6
p-block
IIIA ns2p1
VIIA Halogens, ns2p5
IVA ns2p2
VA ns2p3
VIA Chalcogens, ns2p4
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d-block Transition Metals
3d
4d
5d
6d
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f-block. Inner Transition Metals
4f
5f
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Li
Na
K
Rb
Cs
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Outermost electron configuration
H
He
1s1
1s2
N
B
N
Li
Be
C
O
F
2s1
2s2 2p6
2s2 2p3
2s2 2p2
2s2 2p1
2s2
2s2 2p5
2s2 2p4
Mg
P
S
Cl
Ar
Al
Si
Na
3s2 3p6
3s2 3p5
3s2 3p4
3s2 3p3
3s1
3s2 3p2
3s2 3p1
3s2