Chapter Twenty Two

1
Chapter Twenty Two

• The d-block Elements
• And Coordination Chemistry

2
alkali metals
halogens
alkaline earth
main group elements
18
1
p block
2
13
16
14
17
15
H
He
transition metals d-block elements
2p
Li
B
O
Be
C
2s
F
Ne
N
3p
11
12
3
4
5
7
10
3s
Mg
6
8
9
S
Al
Na
Cl
Si
Ar
P
Noble gasses
4p
3d
Mn
Ge
Sc
Ti
V
Cr
Co
Cu
Zn
Br
4s
K
Ca
Ni
Se
Ga
Kr
Fe
As
5p
4d
5s
Sn
In
Rb
Sr
Xe
I
Te
Sb
6p
6s
5d
Cs
Ba
6d
7s
s block
4f
5f
3
The 3d orbitals
4
General Properties Of The 4th Period
5
General Properties And Their Trends- the1st
Transition Series (the 4th Period)

• All the d-block elements are metals.
• - Electronegativities increase from left to
  right
• - Higher electronegativities than s-block
  elements
• - Compounds with nonmetals are more covalent
• The variability of oxidation number
• - Early transition elements (up to Mn) display
  oxidation number as high as group number
• - Later elements display at most a 3 charged
  ion
• Except for Cu all react with H (aq) to produce
  H2 (g). But only Sc is active enough to
  liberate H2 (g) from water.
• Typical metals with moderate densities and
  melting points, good thermal and electrical
  conductivity.

6
General Properties And Their Trends- the 2nd and
3rd Transition Series

• Elements of the 2nd and 3rd transition series are
  about the same sizes.
• - lanthanide contraction
• - chemically similar
• - The 2nd and 3rd series also exhibit higher
  oxidation numbers than the 1st transition series
  elements.

7
Relative Orbital Energies in theFourth Period
Transition Series
8
Atomic Radii Of The d-Block Elements
9
Oxidation Numbers Of Transition Metals
corresponds to loss of all valence electrons
- frequently seen with oxygen as ligand
2, 3 normal oxidation states for late metals
10
3d transition metals
11
12
3
4
5
7
10
6
8
9
Mn
Sc
V
Cr
Co
Fe
Ti
Cu
Zn
Ni
4s2 3d7
4s2 3d5
4s1 3d10
4s2 3d1
4s2 3d3
4s2 3d10
4s2 3d8
4s1 3d5
4s2 3d6
4s2 3d2
favored oxidation states
3
7 2
2 3
4
5 2
6 3
2 3
2
2
2
11
Scandium

• Scandium oxide was not isolated until 1879, and
  the metal itself was not prepared until 1937.
• Chemistry is based mostly on the Sc3 ion (d0
  valence count).
• In many ways, scandium resembles not the
  transition metals but the main-group metals,
  particularly aluminum.

3d14s2
3
12
Titanium

• Titanium is the 9th most abundant element in
  earths crust and the 2nd most abundant
  transition metal (after iron).
• Desirable properties of Ti metal
• low density
• high structural strength even at high
  temperatures
• corrosion resistance.
• Most important compound of titanium is the oxide,
  TiO2, used as a white pigment in paints, papers,
  and plastics.

3d24s2
3d-transition metals
11
12
3
4
5
7
10
6
8
9
Mn
Sc
Ti
Cr
Co
Fe
V
Cu
Zn
Ni
4
13
Vanadium

• Vanadium is reasonably abundant in Earths solid
  crust, ranking nineteenth among the elements.
• It is mostly obtained as a by-product of the
  production of uranium from carnotite,
  K2(UO2)2(VO4)23H2O.
• Vanadium
• alloying element in steel
• catalytic activity of some of its compounds,
  principally V2O5
• the range of oxidation number in its ions.
• The different oxidation states of vanadium give a
  variety of distinctive colors.

3d34s2
5
14
Chromium

• The most important source of chromium is the
  mineral chromite, FeCr2O4, or FeOCr2O3.
• In addition to its use in alloys, chromium can be
  plated onto other metals, generally by
  electrolysis from a solution containing CrO3 in
  H2SO4.
• Dichromate ion, Cr2O72-, is a common oxidizing
  agent.
• Chromate ion, CrO42-, is a good precipitating
  agent.

3d44s2
3d transition metals
11
12
3
4
5
7
10
6
8
9
Mn
Sc
Ti
Cr
Co
Fe
V
Cu
Zn
Ni
6
15
Manganese

• Manganese is obtained mainly from the mineral
  pyrolusite, MnO2.
• Ferromanganese alloys are wear resistant and
  shock resistant and are used for railroad tracks,
  bulldozers, and road scrapers.
• Manganese dioxide is the starting point for
  making most other manganese compounds.
• Potassium permanganate, KMnO4, is an important
  oxidizing agent.

3d54s2
3d transition metals
11
12
3
4
5
7
10
6
8
9
Mn
Sc
Ti
Cr
Co
Fe
V
Cu
Zn
Ni
7
16
The Iron triad Fe, Co, Ni

• Iron 4th most abundant element in earths
  crust. Co and Ni are not nearly as common, but
  their annual production is still thousands of
  tons.
• used as structural building material, alloy and
  in catalysis
• All three elements form 2 ions. For Co and Ni,
  oxidation state 2 is the most common, bur for Fe
  it is 3. Fe3 has a half-filled 3d subshell, d5.

2, 3
Fe 3d64s2 Co 3d74s2 Ni 3d84s2
17
Hemoglobin
porphyrin ligand heme unit
tetrameric hemoglobin
18
Group 1B Cu, Ag, And Au
19
Group 1B Cu, Ag, And Au

• They are much less active than earlier members of
  their periods.
• They all are difficult to oxidize, and do not
  react with simple strong acids.
• The similar properties of Ag and Au result from
  lanthanide contraction.
• They have physical properties of metals
  malleability, ductility, and high thermal an
  electrical conductivity.
• Sulfuric acid or nitric acid is sufficient to
  oxidize Cu or Ag, but only aqua regia (1 part
  HNO3 3 parts HCl) will oxidize Au.
• Cu (s) 2 H2SO4 (conc. aq) ? CuSO4 (aq) 2 H2O
  SO2 (g)
• 2 Ag (s) 2 H2SO4 (conc. aq) ? Ag2SO4 (aq) 2
  H2O SO2 (g)
• 3 Cu (s) 8 HNO3(aq) ?3 Cu(NO3)2(aq) 4 H2O
  2 NO (g)
• 3 Ag (s) 4 HNO3 (aq) ? 3 AgNO3 (aq) 2 H2O
  NO (g)
• Au(s)4H(aq)NO3-(aq)4Cl-(aq)
  ?AuCl4-(aq)2H2ONO(aq)

20
Zinc

• Zinc has many uses such as in alloys and is a
  good electrical conductor.
• Brass is a copper alloy having from 20 to 45
  zinc and small quantities of tin, lead, and iron.
• Zinc oxidizes in air to form a thin, adherent
  oxide coating that protects the underlying metal
  from further corrosion.
• Because zinc is more easily oxidized than iron,
  zinc is used in making galvanized iron.

21
Cadmium

• Cadmium can substitute for zinc in coating metals
  for certain applications.
• Its primary uses are in alloys and as electrodes
  in batteries.
• Because of its capacity to absorb neutrons,
  cadmium is used in control rods in nuclear
  reactors.
• Whereas zinc in trace amounts is an essential
  element for humans, cadmium is quite toxic.
• Its effect may be to substitute for zinc in
  certain enzymes.

22
Mercury

• Mercury differs from zinc and cadmium in at least
  six significant ways.
• Mercury forms few water-soluble compounds and
  most of its compounds are not hydrated.
• The physical properties of mercury, especially
  its metallic and liquid properties and its high
  density, determine many of its uses.
• Long-term exposure can present a serious health
  hazard.
• Mercury poisons the bodys systems, in part by
  interfering with sulfur-containing enzymes.

23
Some Terminology For Complexes

• A complex consists of a central atom, which is
  usually a metal atom or ion, and attached groups
  called ligands.
• The region surrounding the central atom or ion
  and containing the ligands is called the
  coordination sphere.
• The coordination number is the total number of
  points at which a central atom or ion attaches
  ligands.
• If a complex carries a net electric charge, it is
  called a complex ion.
• A substance consisting of one or more complexes
  is called a coordination compound.

24
Examples of Complex or Complex ion

• complex or coordination central
• complex ion ligands number atom or ion
• Cu(H2O)42 H2O 4 Cu2
• Cu(NH3)42 NH3 4 Cu2
• Pt(NH3)2Cl2 NH3, Cl 4 Pt2
• Ag(NH3)2 NH3 2 Ag
• Fe(CN)64- CN- 6 Fe2

25
Coordination Numbers Geometric Structures

• Coordination No. Geometric Structure
• 2 linear
• 4 square planar or tetrahedral
• 6 octahedral

26
Four Common Structures Of Complex Ions
27
Two Coordination Compounds of Co(III)
CoCl3.5NH3 2 free Cl- per
formula CoCl(NH3)5Cl2
CoCl3.6NH3 3 free Cl- per formula Co(NH3)6
Cl3
28
Ligands

• The atom in a ligand that contains the pair of
  electrons to donate is called donor atom.
• The ligand that bonds to metal atom through one
  atom of the ligand is monodentate.
• A bidentate ligand bonds to a metal atom through
  two atoms of the ligand.
• Polydentate refers to multiple points of
  attachment by one ligand.
• When a five- or six-membered ring is produced by
  the attachment of a polydentate ligand, the
  complex is called a chelate.

29
The Chelate Pt(en)22
H
H
H
H
H
H
C
N
N
H
H
Pt2
C
C
H
H
C
N
N
H
H
H
H
H
H
30
Isomerism In Complex Ions

• Structural isomers differ in the ligands that are
  attached to the central atom or in the donor
  atoms through which the ligands are bonded.
• Geometric isomers differ in the arrangement of
  the attached ligands, forming either cis- (same
  side) or trans- (opposite sides) compounds.
• Optical isomers are isomers that differ in their
  ability to rotate the plane of polarized light.
  Each of the two molecules or ions of an optical
  isomer is called an enantiomer and each
  enantiomer rotates the plane-polarized light in
  opposite directions.

31
Geometric Isomerism In ASquare Planar Complex
32
Geometric Isomerism In AnOctahedral Complex
33
Optical Isomers
34
Summary

• All the elements of the d block are metals.
• Most metals exist in several oxidation states and
  form many complex ions and colored compounds.
• The early members in a period in the d block are
  active metals but later members are less active.
• Scandium resembles aluminum but is not widely
  used.
• The uses of titanium depend on its high strength,
  low density and corrosion resistance.
• Dichromate and permanganate ions are widely used
  oxidizing agents.
• Copper, silver, and gold are much less active
  than earlier members of their periods.

35
Summary

• Zinc, cadmium, and mercury are not transition
  elements their atoms and ions all have filled d
  subshells.
• The central metal atom or ion of a metal complex
  is a Lewis acid it forms coordinate covalent
  bonds by accepting lone-pair electrons from
  ligands, which are Lewis bases.
• Isomerism among complexes is of two general
  types structural and optical.