Transcript periodicity (topics 3 and 13)

IB Chemistry HL2
PERIODICITY (TOPICS 3
AND 13)
Review: Periodic table, Physical and Chemical
Properties of elements (Topic 3)
 Describe the arrangement of elements in the periodic table in order of
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increasing atomic number (5.2.12.A.3)
Distinguish between the terms group and period (5.2.12.A.3)
Apply the relationship between the electron arrangement of elements and their
position in the periodic table up to element n=20 (5.2.12.A.3)
Apply the relationship between the number of electrons in the highest occupied
energy level for an element and its position on the periodic table (5.2.12.A.3)
Define the terms first ionization energy and electronegativity.
Describe and explain the trends in atomic radii, ionic radii, first ionization
energy, electronegativity, and melting points for alkali metals and the halogens.
Describe and explain the trends in atomic radii, ionic radii, first ionization
energies, and electronegativity for elements across period 3 (5.2.12.A.3)
Compare the relative electronegativity of two or more elements based on their
positions in the periodic table.
Discuss the similarities and differences in the chemical properties of elements
in the same group
Discuss the changes in nature, from ionic to covalent and from basic to acidic,
of the oxides across Period 3.
http://www.youtube.com/watch?v=OduTDUGeAXE&feature=player_detailpage
IB note: Inner
transition elements
are of little interest at
this level
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Trends in Atomic Radii
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Comparison of Atomic Radii with Ionic Radii
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Cation is always smaller than atom from
which it is formed.
Anion is always larger than atom from
which it is formed.
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Ionization energy is the minimum energy (kJ/mol) required
to remove an electron from a gaseous atom in its ground
state.
I1 + X (g)
X+(g) + e-
I1 first ionization energy
I2 + X+(g)
X2+(g) + e-
I2 second ionization energy
I3 + X2+(g)
X3+(g) + e-
I3 third ionization energy
I1 < I2 < I3
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General Trends in First Ionization Energies
Increasing First Ionization Energy
Increasing First Ionization Energy
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Electron affinity is the negative of the energy change that
occurs when an electron is accepted by an atom in the
gaseous state to form an anion.
X-(g)
X (g) + e-
F (g) + e-
F-(g)
DH = -328 kJ/mol
EA = +328 kJ/mol
O (g) + e-
O-(g)
DH = -141 kJ/mol
EA = +141 kJ/mol
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Comparison of Group 1A and 1B
The metals in these two groups have similar outer
electron configurations, with one electron in the
outermost s orbital.
Chemical properties are quite different due to difference
in the ionization energy.
Lower I1, more reactive
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Properties of Oxides Across a Period
basic
acidic
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Do NOW
Classify the following oxides as acidic, basic, or amphoteric:
(a)Na2O
(b)P4O10
(c)SO2
Objectives (Topic 13)
Trends Across Period 3
 13.1.1 Explain the physical states (under standard conditions)
and electrical conductivity (in the molten state) of the
chlorides and oxides of the elements in period 3 in terms of
their bonding and structure.
 http://www.youtube.com/watch?v=IHNEe01Dy8Q
 13.1.2 Describe the reactions of chlorine and the chlorides with
water
 http://www.youtube.com/watch?v=9VCSDuwoA8U
First-row d-block elements
13.2.1 List the characteristic properties of transition elements
http://www.youtube.com/watch?v=ZrmJuw_E1G0
13.2.2 Explain why Scandium and Zinc are not considered to
be transition elements.
Sc and Zn do not form colored solutions; due to electronic
configuration of their ions and the lack of partially filled d
orbital.
13.2.3 Explain the existence of variable oxidation number in
ions of transition elements
http://www.youtube.com/watch?v=E3Ok1qaXK_g
Electron Configurations of Cations of Transition Metals
When a cation is formed from an atom of a transition metal,
electrons are always removed first from the ns orbital and
then from the (n – 1)d orbitals.
Fe:
[Ar]4s23d6
Mn:
Fe2+: [Ar]4s03d6 or [Ar]3d6
[Ar]4s23d5
Mn2+: [Ar]4s03d5 or [Ar]3d5
Fe3+: [Ar]4s03d5 or [Ar]3d5
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13.2.4 Define the term ligand.
Ligands are a species (atom or ion) that can donate an electron pair
to a central transition metal atom/ion to form a dative covalent bond.
Common ligands include H2O, CN-, OH- NH3 Cl-.
Ligands must have a lone pair but they do not have to be negative they can be neutral, but never positive.
13.2.5 Describe and explain the formation of complexes of dblock elements.
http://www.youtube.com/watch?v=Lmsn75HLViU
13.2.6 Explain why some complexes of d-block elements
are colored
http://www.youtube.com/watch?v=2nLs0yJqRwk
13.2.7 State examples of the catalytic action of transition
elements and compounds
http://www.youtube.com/watch?v=NIZVXVwvsrA
13.2.8 Outline the economic significance of catalysts in
the Contact and Haber processes.
Iron (Fe) in the Haber process: manufacture of ammoniathe raw material for fertilizers, plastics, drugs, etc.
V2O5 in the Contact process: SO2 + O2  SO3 – for the
manufacture of sulfuric acid, the world’s most important
chemical.
Compounds of the Noble Gases
A number of xenon compounds XeF4, XeO3,
XeO4, XeOF4 exist.
A few krypton compounds (KrF2, for example)
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have been prepared.
Chemistry in Action: Discovery of the Noble Gases
Sir William Ramsay
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