1. Transitional Elements
PowerPoint
Chemistry
Transitional Elements

2. d block) and inner transition elements (f block)

3. USES: Transition Metals
Titanium – excellent structural material (light weight)
Manganese – production of hard steel
Iron – most abundant heavy metal
Cobalt – alloys with other metals
Copper – plumbing and electrical applications
Chromium is electroplated to make shiny metal parts ex: Stainless Steel = 73% Fe,18% Cr, 8% Ni, 1% C
Not these are mostly COLURLESS, but their ions are not as we will see

4. PROPERTIES OF TRANSITION METALS

5. PROPERTIES OF TRANSITION METALS
TRANSITION ELEMENTS:
Lie within the d-block elements
Titanium  Copper
Metals  Conductors of heat & electricity  Shiny, strong & hard  High melting & boiling points
Scandium & Zinc are d-block elements but NOT transition elements…you will see why later!
Physical properties

6. THE FIRST ROW TRANSITION ELEMENTS
Properties strong metallic bonds due to small ionic size and close packing
higher melting, boiling points s-block metals. Many are COLOURED.
Ca Sc Ti V Cr Mn Fe Co
m. pt / °C
density /
g cm
sodium chromate
nickel(II) nitrate hexahydrate
potassium ferricyanide
zinc sulfate heptahydrate
Titanium(IV) oxide
scandium oxide
manganese(II) chloride tetrahydrate
copper(II) sulfate pentahydrate
vanadyl sulfate dihydrate
cobalt(II) chloride hexahydrate

7. PROPERTIES OF TRANSITION METALS
GENERAL PROPERTIES
The general properties of transition metals are:
they form complexes
they form coloured ions
they form variable oxidation states
they have catalytic activity
Chemical properties

8. ELECTRONIC STRUCTURE
All characteristic properties are a result of their electronic structure
The transition metals have a partially filled 3d energy sub level in their atoms or ions
In general there are two outer 4s electrons, and electrons are added to the inner 3d sub level
Check Point 1
What are the full electronic configurations of the elements in the first d-block row? Be careful with Cr and Cu!!!
Extension: Draw box and arrow for 3d and 4s shells

9. FORMING IONS V [Ar] 3d34s2 V3+
In all ions of d-block elements, the 3d subshell is lower in energy than the 4s subshell
So the 4s electrons are always removed first
3d electrons are only removed after all 4s electrons have been removed
To write the electronic structure for Co2+: Co
[Ar] 3d74s2
Co2+
[Ar] 3d7
The 2+ ion is formed by the loss of the two 4s electrons.
To write the electronic structure for V3+: V
[Ar] 3d34s2
V3+
[Ar] 3d2

10. Scandium (Sc) and Zinc (Zn)
Strictly speaking, scandium (Sc) and zinc (Zn) are not transitions elements
∵ Sc forms Sc3+ ion which has an empty d sub-shell (3d0) Zn forms Zn2+ ion which has a completely filled d sub- shell (3d10)
NB: ∵ = ‘therefore’ 10

11. Copper
Cu shows some intermediate behaviour between transition and non-transition elements because of two oxidation states, Cu(I) & Cu(II)
Cu+ is not a transition metal ion as it has a completely filled d sub- shell
Cu2+ is a transition metal ion as it has an incompletely filled d sub-shell 11

12. General Features Transition Metals
Transition elements have similar atomic radii which make them possible for the atom of one element to replace those of another element in the formation of alloy
e.g. Mn is for conferring hardness and wearing resistance to its alloy (duralumin)
Cr is for conferring inertness on stainless steel 12

13. General Features Transition Metals
Iron is used to make ships
Ramstore Bridge (Astana) - constructed using steel 13

14. General Features Transition Metals
Tungsten in a light bulb
The statue is made of alloy of copper and zinc
Titanium is used in making aircraft
Jewellery made of gold 14

15. General Features Transition Metals
Variations in atomic and ionic radii of the first series of d-block elements 15

16. General Features Transition Metals
The atomic size reduces at the beginning of the series
∵ increase in effective nuclear charge with atomic numbers
 the electron clouds are pulled closer to the nucleus
 causing a reduction in atomic size
The atomic size decreases slowly in the middle of the series
∵ when more and more electrons enter the inner 3d sub- shell
 the screening and repulsive effects of the electrons in the 3d sub-shell increase
 the effective nuclear charge increases slowly 16

17. General Features Transition Metals
The atomic size increases at the end of the series
∵ the screening and repulsive effects of the 3d electrons reach a maximum
The reasons for the trend of the ionic radii of the d-block elements are similar to those for the atomic radii.
Remember that the electrons have to be removed from the 4s orbital first 17

18. Variable oxidation state
Observations:
1. Sc and Zn do not exhibit variable oxidation states. Sc3+ has electronic configuration of argon (i.e. 1s22s22p63s23p6). Zn2+ has the electronic configuration of [Ar] 3d10. Other oxidation states are not possible.
2. Except Sc, all elements have +2 oxidation state. Except Zn, all elements have +3 oxidation state
3. The highest oxidation state is +7 at Mn. This corresponds to removal of all 3d & 4s electrons. (Note: max.oxidation state is NEVER greater than the total number of 3d & 4s electrons) 18

19. Variable oxidation state
4. There is a reduction in the number of oxidation states after Mn. ∵ decrease in the number of unpaired electrons and increase in nuclear charge which holds the 3d electrons more firmly
5. The relative stability of various oxidation states can be correlated -with the stability of empty, half-filled and fully- filled configuration
e.g. Ti4+ is more stable than Ti3+ (∵ [Ar]3d0 configuration) Mn2+ is more stable than Mn3+ (∵ [Ar]3d5 configuration) Zn2+ is more stable than Zn+ (∵ [Ar]3d10 configuration) 19

20. The Reactions and their Colours Do you recall
The Reactions and their Colours Do you recall? Now you will see why these colours exist
Metal
Aqueous
ion
NaOH goes Neutral ppt
NaOH excess
NH3(aq)
SAME AS NaOH base
Excess
Na2CO3(aq)
Weak Base
ppts are Neutral Fe
(II)
Green
[Fe(H2O)6]2+(aq)
GREEN ppt
Fe(H2O)4(OH)2(s)
No change
Green ppt
FeCO3(s)
2+ not able to be acid
(III)
Yellowish
[Fe(H2O)6]3+(aq)
Brown ppt
Fe(H2O)3(OH)3(s)
Acid Base Rx
Bubbles of CO 2(g) Cu
Blue
[Cu(H2O)6]2+(aq)
BLUE ppt
Cu(H2O)4(OH)2(s)
DEEP BLUE
[Cu(H2O)2(NH3)4]2+(aq)
Blue-Green ppt
CuCO3(s) Al
[Al(H2O)6]3+(aq)
WHITE ppt
Al(H2O)3(OH)3(s)
[Al(OH)4]–(aq)
Colorless
Bubbles of CO2(g)

21. Formulas of Coordination Compounds
Rules for writing formulas:
1. The cation is written first
2. In the complex ion, neutral ligands are written before anionic ligands, and the formula for the whole ion is placed in brackets.
3. Ligands are named, in alphabetical order, before the metal ion.
If the complex ion is an anion the metal name must end with –ate
and with Latin names (see table) where possible

22. Nomenclature of Complexes
Complexes are named according to the rules recommended by IUPAC
The rules of naming a complex are as follow:
1. (a) For any ionic compound, the cation is named before the anion.
(b) If the compound is neutral, then the name of the complex is name of the compound
(c) In naming a complex, the ligands are named before the central metal atom or ion, negative ones first and then neutral ones 22

23. Nomenclature of Complexes
(d) The number of each type of ligands are specified by the Greek prefixes: mono-, di-, tri-, tetra-, penta-, hexa-, etc.
(e) The oxidation number of the metal ion in the complex is named immediately after it by Roman numerals
Therefore, K3[Fe(CN)6] potassium hexacyanoferrate(III) [CrCl2(H2O)4]Cl dichlorotetraaquachromium(III) chloride [CoCl3(NH3)] trichlorotriamminecobalt(III) Note: in the formulae, the complexes are always enclosed in [ ] 23

24. Nomenclature of Complexes
2. (a) The root names of anionic ligands always end in -o. e.g. CN– cyano Cl– chloro
(b) The names of neutral ligands are the names of the molecules, except NH3, H2O, CO and NO e.g. NH3 ammine H2O aqua
Anionic ligand
Name of ligand
Neutral ligand
Bromide (Br–)
Chloride (Cl–)
Cyanide (CN–)
Fluoride (F–)
Hydroxide (OH–)
Sulphate(VI) (SO42–)
Amide (NH2–)
Bromo
Chloro
Cyano
Fluoro
Hydroxo
Sulphato
Amido
Ammonia (NH3)
Water (H2O)
Carbon monoxide (CO)
Nitric oxide (NO)
Ammine
Aqua
Cabonyl
Nitrosyl 24

25. Nomenclature of Complexes
3. (a) If the complex is anionic, then the suffix -ate is attached to the name of the metal, followed by the oxidation state of that metal
e.g. K2CoCl4 potassium tetrachlorocobaltate(II) K3Fe(CN)6 potassium hexacyanoferrate(III) [CuCl4]2– tetrachlorocuprate(II) ion 25

26. Name in anionic complex
Nomenclature of Complexes
Metal
Name in anionic complex
Titanium
Chromium
Manganese
Iron
Cobalt
Nickel
Copper
Zinc
Platinum
Titanate
Chromate
Manganate
Ferrate
Cobaltate
Nickelate
Cuprate
Zincate
Platinate
(b) If the complex is cationic or neutral, then the name of the metal is unchanged. e.g. [CrCl2(H2O)4]+ dichlorotetraaquachromium(III) ion [CoCl3(NH3)3] trichlorotriamminecobalt(III) 26

27. Nomenclature of Complexes
Examples:
1. Ionic complexes 27

28. Nomenclature of Complexes
2. Neutral complex 28

29. COMPLEX FORMATION Check Point 5
Work out the oxidation states (OS) and co-ordination numbers (CN) of the following complexes:
[Cu(H2O)6]2+ OS: +2 CN:6
[Ag(NH3)2]+ OS: +1 CN:2
[Cu(NH3)4]2+ OS: +2 CN:4
[Cu(Cl)4] OS: +2 CN:4
[Fe(CN)6] OS: +3 CN:6

30. sodium hexafluoroaluminate
Writing Names and Formulas of Coordination Compounds
PROBLEM:
(a) What is the systematic name of Na3[AlF6]?
(b) What is the formula of tetraaminebromochloroplatinum(IV) chloride?
(c) What is the formula of hexaaminecobalt(III) bromide?
SOLUTION:
(a) The complex ion is [AlF6]3-.
Six (hexa-) fluorines (fluoro-) are the ligands - hexafluoro
Aluminum is the central metal atom – aluminate –ends in ATE because it is negative
Aluminum has only the +3 ion so we don’t need Roman numerals.
sodium hexafluoroaluminate

31. Writing Names and Formulas of Coordination Compounds
tetraamminebromochloroplatinum(IV) chloride
(b)
4 NH3
Br-
Cl-
Pt4+
Cl-
[Pt(NH3)4BrCl]Cl2
(c)
hexaamminecobalt(III) Bromide
6 NH3
Co3+
bromide
[Co(NH3)6]Br3

32. Exercise (a) [Co(H2O)6]Br3 (b) Na2[PtCl4]
Name the following coordination compounds.
(a) [Co(H2O)6]Br3 (b) Na2[PtCl4]
a) hexaaquacobalt(III) bromide
b) sodiumtetrachloro-platinate(II)
(a) Hexaaquacobalt(III) bromide
(b) Sodium tetrachloroplatinate(II) (ate because it is a anion)

33. Try a few Ends with ate as is an anion [CuCl4]2- [Cu(H2O)6]2+
Complex Ion
Name
Cr[Cl4(OH2)2]-
Ends with ate as is an anion
diaquatetrachlorochromate (III) io
[Cr(OH2)(NH3)5]3+
pentaammineaquachromium (III) ion
[Al(OH)Cl3]-
trichlorohydroxoaluminate (III) ion
[CrCl2(OH2)4]+
tetraaquadichlorochromium (III) ion
Formula
Name
[CuCl4]2-
tetrachlorochromium (II) ion
Formula
Name
[Cu(H2O)6]2+
Hexaaquacopper(II) ion

34. ELECTRONIC CONFIGURATIONS (and some Ions)
Note: Removing e- from the highest level of n FIRST(or largest number)
Sc 1s2 2s2 2p6 3s2 3p6 4s2 3d1
Ti 1s2 2s2 2p6 3s2 3p6 4s2 3d2
Chromium is an exception
Cr 1s2 2s2 2p6 3s2 3p6 4s1 3d5
Mn 1s2 2s2 2p6 3s2 3p6 4s2 3d5
Fe 1s2 2s2 2p6 3s2 3p6 4s2 3d6
Co 1s2 2s2 2p6 3s2 3p6 4s2 3d7
Ni 1s2 2s2 2p6 3s2 3p6 4s2 3d8
Cu 1s2 2s2 2p6 3s2 3p6 4s1 3d10
Zn 1s2 2s2 2p6 3s2 3p6 4s2 3d10
Sc3+ 1s2 2s2 2p6 3s2 3p6 4s2 3d1
Ti s2 2s2 2p6 3s2 3p6 4s2 3d2
Ti s22s2p63s23p6 4s2 3d2 goes to 3d1
Ti s2 2s2 2p6 3s2 3p6
Mn can have 7 ions
An exception
Cu. 1s2 2s2 2p6 3s2 3p6 3d10 4s1
Cu+ 1s2 2s2 2p6 3s2 3p6 3d10
Cu2+ 1s2 2s2 2p6 3s2 3p6 3d9
Zn s2 2s2 2p6 3s2 3p6 4s2 3d10

35. Finding the Number of Unpaired Electrons
PROBLEM:
The alloy SmCo5 forms a permanent magnet because both samarium and cobalt have unpaired electrons. How many unpaired electrons are in the Sm atom (Z = 62)?
SOLUTION:
Sm is the 8th element after Xe. Two electrons go into the 6s sublevel and the remaining six electrons into the 4f (which fills before the 5d).
Sm is [Xe]6s24f 6 6s 4f
There are 6 unpaired e− in Sm., the more
UNPAIRED electrons, the more magnetic

36. Concept Check
What is the expected electron configuration of Sc+? Explain.
[Ar]3d2
Normally Sc electronic config = 1s2 2s2 2p6 3s2 3p6 4s2 3d1
To create an ion you take way from the highest level of n.
The electron configuration for Sc+ is [Ar]3d2. The 3d orbitals are lower in energy than the 4s orbitals for ions. Students need to know this when they draw energy level diagrams using the Crystal Field model.

37. CHROMIUM AN EXCEPTION 1s2 2s2 2p6 3s2 3p6 4s1 3d5
ELECTRONIC CONFIGURATIONS OF THE FIRST ROW TRANSITION METALS
CHROMIUM
AN EXCEPTION 4 4p 4d 4f
INCREASING ENERGY / DISTANCE FROM NUCLEUS 3d 4s 3 3p
1s2 2s2 2p6 3s2 3p6 4s1 3d5
One would expect the configuration of chromium atoms to end in 4s2 3d4.
To achieve a more stable arrangement of lower energy, one of the 4s electrons is promoted into the 3d to give six unpaired electrons with lower repulsion.
Half filled d orbitals are more stable

38. Cations are positive (“pussy-tive) ions
COMPLEX FORMATION
COMPLEXES
Complexes are formed when transition metals or their ions form co-ordinate (dative) bonds with ligands
A complex ion is an ion comprising of one or more ligands attached to a central metal cation by means of a dative covalent bond
Cations are positive (“pussy-tive) ions

39. COMPLEX FORMATION LIGANDS
A ligand is a species which can use its lone pair of electrons on one of its atoms to form a dative covalent bond with a transition metal
Examples of ligands are:
H2O
NH3
Cl-
OH-
CN-

40. COMPLEX FORMATION CO-ORDINATE BOND
A co-ordinate bond (dative covalent bond) is a covalent bond in which both electrons come from the same atom
In the case of complex ions, the co-ordinate bonds are formed by the overlap of an orbital containing a lone pair of electrons with a vacant orbital on the transition metal

41. COMPLEX FORMATION CO-ORDINATION NUMBER
The number of lone pairs of electrons which a cation can accept is known as the coordination number of the cation
It depends on the size and electronic configuration of that cation, and also on the size and charge of the ligand
Coordination number 6 is the most common, although 4 and 2 are also known

42. COMPLEX FORMATION LEWIS ACID / BASE In complexes:
The metal ion acts as a Lewis Acid
Accepts lone pairs of electrons
The ligand acts as a Lewis Base
Donates lone pairs of electrons
Lewis Acid  electron pair acceptor
Lewis Base  electron pair donor

43. COMPLEX FORMATION EXAMPLE An example of a complex ion is: [Cu(H2O)6]2+
Note that the formula of the ion is always written inside square brackets
The overall charge is written outside the brackets
H2O
Cu2+
OH2

44. COMPLEX FORMATION MONODENTATE LIGANDS/UNIDENTATE
Meaning ‘single toothed’  form 1 co-ordinate bond
Common unidentate ligands are H2O, Cl-, NH3 and CN-
Can be negatively charged ions or neutral molecules
Ammonia only has 1 pair of electrons to donate
Water has 2 lone pairs. BUT they are so close together it can only form one coordinate bond at a time!

45. 2 amine groups. Each has a lone pair of electrons to donate
COMPLEX FORMATION
BIDENTATE LIGANDS
Ligands that can form two co-ordinate bonds since they donate two lone pairs of electrons (from two donor atoms)
Examples:
Ethane-1,2-diamine (NH2CH2CH2NH2)
Each ethane-1,2-diamine molecule forms 2 coordinate bonds with the metal ion
2 amine groups. Each has a lone pair of electrons to donate

46. COMPLEX FORMATION MULTIDENTATE LIGANDS
Can form three or more co-ordinate bonds by donating at least three lone pairs of electrons to the metal ion
Extremely stable since the reaction results in an increase in entropy
EDTA is a common example
How many coordinate bonds can it form?
Ethylenediaminetetracetate

47. COMPLEX FORMATION
EDTA4- has six lone pairs (two on nitrogen atoms and 4 on oxygen atoms)
It can form six coordinate bonds with a metal ion
Complex ions with multidentate ligands are called chelates (‘key-lates) from the Greek word for claw

48. COPPER AN EXCEPTION 1s2 2s2 2p6 3s2 3p6 4s1 3d10
ELECTRONIC CONFIGURATIONS OF THE FIRST ROW TRANSITION METALS
COPPER
AN EXCEPTION 4 4p 4d 4f
INCREASING ENERGY / DISTANCE FROM NUCLEUS 3d 4s 3 3p
1s2 2s2 2p6 3s2 3p6 4s1 3d10
One would expect the configuration of copper atoms to end in 4s2 3d9.
To achieve a more stable arrangement of lower energy, one of the 4s electrons is promoted into the 3d to make it fully filled.

49. Unidentate ligands – form one co-ordinate bond
COMPLEX FORMATION
Unidentate ligands – form one co-ordinate bond
e.g. H2O: :OH- :NH :CN :Cl-
Question. Cu with water then with Cl-, what would it be?
[Cu(H2O)6]2+
Hexaaquacopper(II)
[CuCl4] 2- it is an anion -ate
tetrachlorochromate (II) ion
Shape:
OCTAHEDRAL
Shape
TETRAHEDRAL

50. Bidentate ligands – form two co-ordinate bonds
COMPLEX FORMATION
Bidentate ligands – form two co-ordinate bonds
ethanedioate
(C2O42-)
1,2-diaminoethane
Or ethandiamine
e.g. [Cr(NH2CH2CH2NH2)3]3+
e.g. [Cr(C2O4)3]3- O

51. Ethandiaminetetraacetocobalt(II)
COMPLEX FORMATION
Multidentate ligands – form several
co-ordinate bonds
EDTA4-
Union of ethanediamine and tetra ethanoic acid
e.g. can you name this ion [Co(EDTA)]2- ?
Ethandiaminetetraacetocobalt(II)

52. Ligands possess one or more lone pair of electrons
SUMMARY LIGANDS
Ligands possess one or more lone pair of electrons
Thus they are Lewis Bases
chloro
Cl-
amine
NH3
 unidentate
cyano
CN-
aqua
H2O
hydroxo
OH-
oxalate (ox)
C2O42-
bidentate
ethylenediaminetetraacetato
 (EDTA)
(COOH)2N(CH)2N(COOH)2
hexadentate
Ligands form co-ordinate bonds to the central ion by donating a lone pair : into vacant orbitals on the central species
Bidentate form two co-ordinate bonds
H2NCH2CH2NH C2O42-

53. EDTA – A sexidentate ligand or 6 Claws
ethylenediamminetetraacetate ion (EDTA4-),
Applications: As a chelating Agent ( chelating = claw )
EDTA4- is used to "trap" trace amounts of transition metals that could potentially catalyze the decomposition of the product.
The sodium salt of EDTA4- (i.e., Na4EDTA) can be found in many commercial products including:
soap
beer
mayonnaise

54. COMPLEX FORMATION
Multidentate ligands – form several co-ordinate bonds
Actual porphyrin
Eg. haem
haemoglobin

55. CO-ORDINATION NUMBER & SHAPE
The shape of a complex is governed by the number of ligands or DATIVE BONDS around the central ion
Co-ordination No. Shape Example(s)
6 Octahedral [Cu(H2O)6]2+
4 Tetrahedral [CuCl4]2-
4 Square planar Pt(NH3)2Cl2
2 Linear [Ag(NH3)2]+

56. COMPLEX FORMATION TERMS
Ligand
particle with a lone pair that forms co-ordinate bond to metal
Complex
metal ion with ligands co-ordinately bonded to it
Co-ordination number
number of co-ordinate bonds from ligand(s) to metal ions
lone pair donor (ligands are Lewis bases)
Eg :Cl -
Lewis base
Lewis acid
lone pair acceptor Cu2+

57. SHAPES OF COMPLEX IONS Co-ordination number 2 4 6 Shape linear
tetrahedral
square planar
octahedral
Bond angles
180º
109½º
90º
Occurrence
Ag+ complexes
Large ligands (e.g. Cl-)
Pt2+
complexes
Commonest
e.g.
[Ag(NH3)2]+
[CuCl4]2-
[PtCl4]2-
[Cu(H2O)6]2+

58. STEREOISOMERISM IN COMPLEXES
E-Z Isomerism
e.g. [PtCl2(NH3)2]
cis
trans

59. CIS-PLATIN Very effective drug to fight cancer (e.g. testicular)
Binds to guanine in DNA and stops replication

60. STEREOISOMERISM IN COMPLEXES
E-Z Isomerism
e.g. [CoCl2(NH3)4]+