Transcript Chapter 1: Matter and Measurement

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
Prentice-Hall © 2002
(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
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
10-4 Ionization Energy
Quantity of energy a gaseous atom must absorb so
that an electron is stripped from it. This energy
increases going from bottom to top in a group and left
to right in a period.
Mg(g) → Mg+(g) + e-
I1 = 738 kJ
Mg+(g) → Mg2+(g) + e-
I2 = 1451 kJ
Zeff2
EI = RH 2
n
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As Zeff increases, so does the EI
As n increases, EI decreases.
General Chemistry: Chapter 9
First Ionization Energy
Notice the
noble gases
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General Chemistry: Chapter 9
Ionization Energies for n=3 Elements
Table 10.4 Ionization Energies of the
Third-Period Elements (in kJ/mol)
737.7
577.6
1012
999.6
1451
7733
I2 (Mg) vs. I3 (Mg)
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I1 (Mg) vs. I1 (Al)
General Chemistry: Chapter 9
I1 (P) vs. I1 (S)
10-5 Electron Affinity
Energy change occurring when a gaseous atom gains
an electron.
F(g) + e- → F-(g)
EA = -328 kJ
F(1s22s22p5) + e- → F-(1s22s22p6)
Li(g) + e- → Li-(g)
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General Chemistry: Chapter 9
EA = -59.6 kJ
First Electron Affinities
Values in kJ mol-1
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General Chemistry: Chapter 9
Second Electron Affinities
O(g) + e- → O-(g)
EA1 = -141 kJ
O-(g) + e- → O2-(g)
EA2 = +744 kJ
The positive value of EA2 makes the formation of O2unlikely. However, in ionic compounds (such as
MgO) other energetically favourable processes are
able to overcome this positive energy.
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General Chemistry: Chapter 9
10-6 Magnetic Properties
• Diamagnetic atoms or ions:
– All e- are paired.
– Weakly repelled by a magnetic field.
• Paramagnetic atoms or ions:
– Unpaired e-.
– Attracted to an external magnetic field.
Attraction is proportional to # unpaired e-
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General Chemistry: Chapter 9
Paramagnetism
Paramagnetism
corresponding to
5 unpaired
electrons.
Paramagnetism
corresponding to
4 unpaired
electrons.
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General Chemistry: Chapter 9
10-7 Periodic Properties of the Elements
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General Chemistry: Chapter 9
Boiling Point
The value of a property
often changes uniformly
from the top to the bottom
of a group of elements in
the periodic table.
?
266
F2
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m.p. 53 K,
General Chemistry: Chapter 9
?
332
b.p. 85 K
Melting Points of Elements
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General Chemistry: Chapter 9
Melting Points of Compounds
Special intermolecular forces
become important for HF
resulting in the deviation.
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General Chemistry: Chapter 9
Reducing Ability of Group 1 and 2 Metals
2 K(s) + 2 H2O(l) → 2 K+ + 2 OH- + H2(g)
I1 = 419 kJ
I1 = 590 kJ
I2 = 1145 kJ
Ca(s) + 2 H2O(l) → Ca2+ + 2 OH- + H2(g)
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General Chemistry: Chapter 9
Oxidizing Abilities of the Halogens
2 Na + Cl2 → 2 NaCl
Cl2 + 2 I- → 2 Cl- + I2
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General Chemistry: Chapter 9
Acid Base Nature of Element Oxides
• Basic oxides or base anhydrides:
Li2O(s) + H2O(l) → 2 Li+(aq) + 2 OH-(aq)
• Acidic oxides or acid anhyhydrides:
SO2 (g) + H2O(l) → H2SO3(aq)
• Na2O and MgO yield basic solutions
• Cl2O, SO2 and P4O10 yield acidic solutions
• SiO2 dissolves in strong base, acidic oxide.
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General Chemistry: Chapter 9
Focus on The Periodic Law and Mercury
• Should be a solid.
• Lowering in energy of
6s orbital and stability
of electron
configuration weakens
bonds in between
individual Hg atoms.
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General Chemistry: Chapter 9
Chapter 10 Questions
1, 2, 18, 21,
27, 33, 39,
43, 51, 52,
55
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General Chemistry: Chapter 9