Lecture 21-Chapter 9_10-November 4, 2005

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Transcript Lecture 21-Chapter 9_10-November 4, 2005

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
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• Magnetic quantum number,
ml= - l …-2, -1, 0, 1, 2…+l
• Magnetic spin number,
ms= + ½ , - ½
General Chemistry: Chapter 9
Quantum Numbers and the Periodic Table
l = 0, m = 0, m = +/- ½
l
l = 1, ml = -1, 0, 1, ms = +/- ½
s
n=1
l = 2, m = -2, -1, 0, 1, 2, m = +/- ½
n=2
n=3
n=4
l
s
s
p
d
n=5
n=6
n=7
f
l = 3, ml = -3, -2, -1, 0, 1, 2, 3, ms = +/- ½
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General Chemistry: Chapter 9
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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General Chemistry: Chapter 9
Sample Question
Write the electron configuration of chlorine. Identify both the
the core and valence electrons. Is this element paramagnetic
or diamagnetic?
1s2
2s2
2p6
3p5
3s2
core electrons (neon core)
valence electrons
The unpaired electron makes chlorine paramagnetic.
If all electrons were paired, it would be diamagnetic.
Cl: 1s22s22p63s23p5
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or
[Ne]3s23p5
General Chemistry: Chapter 9
Sample Question
•
Concerning the electrons in the shells, subshells
and orbitals of an atom, how many can have:
a) n = 3, l = 2, ml = 0, ms = + ½
Only one electron can have these 4 quantum numbers
b) n = 3, l = 2, ml = 0,
Two electrons can have these 3 quantum numbers
c) n = 3, l = 2,
Ten electrons can have these 2 quantum numbers
d) n = 3
Eighteen electrons can have this quantum number
e) n = 3, l = 2, ms = + ½
Five electrons can have these quantum numbers
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General Chemistry: Chapter 9
Summary
• Frequency, wavelength, velocity
v=c/l
• Quantum Theory
E = h v = hc/l
• Photoelectric effect
• Bohr Atom (orbital energy levels)
En = -RH / n2
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General Chemistry: Chapter 9
Summary
• Ionization Energy
En = -Z2 RH / n2
• Wave-Particle Duality
l = h/p = h/mu
• Quantum Numbers and Electron Orbitals
n, l, ml, ms
s, p, d, f
shapes of orbitals
• Assigning Electrons to orbitals
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General Chemistry: Chapter 9
Chapter 9 Questions
1, 2, 3, 4, 12,
15, 17, 19, 22,
25, 34, 35, 41,
67, 69, 71, 83,
85, 93, 98
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General Chemistry: Chapter 9
General Chemistry
Principles and Modern Applications
Petrucci • Harwood • Herring
8th Edition
Chapter 10: The Periodic Table and
Some Atomic Properties
Philip Dutton
University of Windsor, Canada
N9B 3P4
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(modified 2003 by Dr. Paul Root and
2005 by Dr. David Tramontozzi)
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General Chemistry: Chapter 10
Contents
10-1 Classifying the Elements: The Periodic
Law and the Periodic Table
10-2 Metals and Nonmetals and Their Ions
10-3 The Sizes of Atoms and Ions
10-4 Ionization Energy
10-5 Electron Affinity
10-6 Magnetic Properties
10-7 Periodic Properties of the Element
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General Chemistry: Chapter 10
10-1 Classifying the Elements: The
Periodic Law and the Periodic Table
• 1869, Dimitri Mendeleev
Lother Meyer
When the elements are arranged in order of
increasing atomic mass, certain sets of
properties recur periodically.
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General Chemistry: Chapter 10
Periodic Law
Meyer’s results
High atomic
volumes occur
periodically for
the alkali metals.
Other physical
properties such
as hardness,
compressibility
and bp’s are
found to repeat
periodically
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General Chemistry: Chapter 10
Mendeleev’s Periodic Table
1871
—
= 44
—
= 68
—
= 72
—=
100
Mendeleev’s table left holes for yet to be discovered
elements. Similar elements fall in vertical groups and
properties change gradually from top to bottom
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General Chemistry: Chapter 10
Predicted Elements were Found
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General Chemistry: Chapter 10
X-Ray Spectra
• Moseley 1913
–X-ray emission is
explained in terms of
transitions in which edrop into orbits close
to the atomic nucleus.
–Correlated frequencies
to nuclear charges.
•  = A (Z – b)2
–Used to predict new
elements (43, 61, 75)
later discovered.
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General Chemistry: Chapter 10
Alkali Metals
The Periodic table
Alkaline Earths
Halogens
Main Group
Transition Metals
Main Group
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Lanthanides and Actinides
General Chemistry: Chapter 10
Noble Gases
10-2 Metals and Nonmetals and Their Ions
• Metals
– Good conductors of heat and electricity.
– Malleable and ductile.
– Moderate to high melting points.
• Nonmetals
– Nonconductors of heat and electricity.
– Brittle solids.
– Some are gases at room temperature.
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General Chemistry: Chapter 10
Metals Tend to Lose Electrons
Lose enough electrons to attain a noble gas electron
configuration.
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General Chemistry: Chapter 10
Nonmetals Tend to Gain Electrons
Gain enough electrons to attain a noble gas electron
configuration.
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General Chemistry: Chapter 9
Electron Configuration of Some Ions
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General Chemistry: Chapter 9
10-3 The Sizes of Atoms and Ions
½ the distance between the
nuclei of two identical atoms
joined by a single covalent
bond
½ the distance between the
nuclei of two identical metal
atoms in a crystalline solid.
The distance between the nuclei
of ions joined by an ionic bond.
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General Chemistry: Chapter 9
Atomic Radius
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General Chemistry: Chapter 9
Screening and Penetration
Zeff = Z – S
Zeff2
En = - RH 2
n
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General Chemistry: Chapter 9
Cationic Radii
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General Chemistry: Chapter 9
Anionic Radii
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General Chemistry: Chapter 9
Atomic and Ionic Radii
Cations are smaller than
atoms from which formed.
For isoelectronic cations,
more positive charge,
smaller radius.
Anions, larger than
corresponding. For
isoelectronic anions,
more negative charge,
larger radius.
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General Chemistry: Chapter 9
In general, atomic
radius increases
going from top to
bottom in a group
In general, atomic
radius decreases
going from left to
right across a period