1. KNOCKHARDY PUBLISHING
AN INTRODUCTION TO
TRANSITION METAL
CHEMISTRY
KNOCKHARDY PUBLISHING

2. DEFINITION OF TRANSITION ELEMENTS
Definition D-block elements forming one or more stable ions with
partially filled (incomplete) d-sub shells.
Properties arise from an incomplete d sub-shell in atoms or ions

3. THE FIRST ROW TRANSITION ELEMENTS
Metallicproperties All the transition elements are metals Strong metallic bonds due to small ionic size and close packing Higher melting, boiling points and densities than s-block metals
K Ca Sc Ti V Cr Mn Fe Co
m.p. (°C)
density
(g cm-3 )

4. ELECTRONIC CONFIGURATIONS OF THE FIRST ROW TRANSITION METALS
POTASSIUM 4 4p 4d 4f
INCREASING ENERGY / DISTANCE FROM NUCLEUS 3d 4s 3 3p
1s2 2s2 2p6 3s2 3p6 4s1
‘Aufbau’ Principle
In numerical terms one would expect the 3d orbitals to be filled next.
However, because the principal energy levels get closer together as you go further from the nucleus coupled with the splitting into sub energy levels, the 4s orbital is of a LOWER ENERGY than the 3d orbitals so gets filled first.

5. ELECTRONIC CONFIGURATIONS OF THE FIRST ROW TRANSITION METALS
CALCIUM 4 4p 4d 4f
INCREASING ENERGY / DISTANCE FROM NUCLEUS 3d 4s 3 3p
1s2 2s2 2p6 3s2 3p6 4s2
As expected, the next electron in pairs up to complete a filled 4s orbital.
This explanation, using sub levels fits in with the position of potassium and calcium in the Periodic Table. All elements with an -s1 electronic configuration are in Group I and all with an -s2 configuration are in Group II.

6. ELECTRONIC CONFIGURATIONS OF THE FIRST ROW TRANSITION METALS
SCANDIUM 4 4p 4d 4f
INCREASING ENERGY / DISTANCE FROM NUCLEUS 3d 4s 3 3p
1s2 2s2 2p6 3s2 3p6 4s2 3d1
With the lower energy 4s orbital filled, the next electrons can now fill p the 3d orbitals. There are five d orbitals. They are filled according to Hund’s Rule.
BUT WATCH OUT FOR TWO SPECIAL CASES.

7. ELECTRONIC CONFIGURATIONS OF THE FIRST ROW TRANSITION METALS
TITANIUM 4 4p 4d 4f
INCREASING ENERGY / DISTANCE FROM NUCLEUS 3d 4s 3 3p
1s2 2s2 2p6 3s2 3p6 4s2 3d2
The 3d orbitals are filled according to Hund’s rule so the next electron doesn’t pair up but goes into an empty orbital in the same sub level.
HUND’S RULE OF
MAXIMUM MULTIPLICITY

8. ELECTRONIC CONFIGURATIONS OF THE FIRST ROW TRANSITION METALS
VANADIUM 4 4p 4d 4f
INCREASING ENERGY / DISTANCE FROM NUCLEUS 3d 4s 3 3p
1s2 2s2 2p6 3s2 3p6 4s2 3d3
The 3d orbitals are filled according to Hund’s rule so the next electron doesn’t pair up but goes into an empty orbital in the same sub level.
HUND’S RULE OF
MAXIMUM MULTIPLICITY

9. ELECTRONIC CONFIGURATIONS OF THE FIRST ROW TRANSITION METALS
CHROMIUM 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.

10. ELECTRONIC CONFIGURATIONS OF THE FIRST ROW TRANSITION METALS
MANGANESE 4 4p 4d 4f
INCREASING ENERGY / DISTANCE FROM NUCLEUS 3d 4s 3 3p
1s2 2s2 2p6 3s2 3p6 4s2 3d5
The new electron goes into the 4s to restore its filled state.

11. ELECTRONIC CONFIGURATIONS OF THE FIRST ROW TRANSITION METALS
IRON 4 4p 4d 4f
INCREASING ENERGY / DISTANCE FROM NUCLEUS 3d 4s 3 3p
1s2 2s2 2p6 3s2 3p6 4s2 3d6
d orbitals are filled according to Hund’s Rule. Electrons continue to pair up.
HUND’S RULE OF
MAXIMUM MULTIPLICITY

12. ELECTRONIC CONFIGURATIONS OF THE FIRST ROW TRANSITION METALS
COBALT 4 4p 4d 4f
INCREASING ENERGY / DISTANCE FROM NUCLEUS 3d 4s 3 3p
1s2 2s2 2p6 3s2 3p6 4s2 3d7
Orbitals are filled according to Hund’s Rule. They continue to pair up.
HUND’S RULE OF
MAXIMUM MULTIPLICITY

13. ELECTRONIC CONFIGURATIONS OF THE FIRST ROW TRANSITION METALS
NICKEL 4 4p 4d 4f
INCREASING ENERGY / DISTANCE FROM NUCLEUS 3d 4s 3 3p
1s2 2s2 2p6 3s2 3p6 4s2 3d8
Orbitals are filled according to Hund’s Rule. They continue to pair up.
HUND’S RULE OF
MAXIMUM MULTIPLICITY

14. ELECTRONIC CONFIGURATIONS OF THE FIRST ROW TRANSITION METALS
COPPER 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.
HUND’S RULE OF
MAXIMUM MULTIPLICITY

15. ELECTRONIC CONFIGURATIONS OF THE FIRST ROW TRANSITION METALS
ZINC 4 4p 4d 4f
INCREASING ENERGY / DISTANCE FROM NUCLEUS 3d 4s 3 3p
1s2 2s2 2p6 3s2 3p6 4s2 3d10
The electron goes into the 4s to restore its filled state and complete the 3d and 4s orbital filling.

16. ELECTRONIC CONFIGURATIONS
K 1s2 2s2 2p6 3s2 3p6 4s1
Ca 1s2 2s2 2p6 3s2 3p6 4s2
Sc 1s2 2s2 2p6 3s2 3p6 4s2 3d1
Ti 1s2 2s2 2p6 3s2 3p6 4s2 3d2
V 1s2 2s2 2p6 3s2 3p6 4s2 3d3
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

17. VARIABLE OXIDATION STATES
Arises from the similar energies required for removal of 4s and 3d electrons
When electrons are removed they come from the 4s orbitals first
Cu 1s2 2s2 2p6 3s2 3p6 3d10 4s Ti 1s2 2s2 2p6 3s2 3p6 3d2 4s2
Cu+ 1s2 2s2 2p6 3s2 3p6 3d Ti2+1s2 2s2 2p6 3s2 3p6 3d2
Cu2+ 1s2 2s2 2p6 3s2 3p6 3d Ti3+1s2 2s 2p6 3s2 3p6 3d Ti4+1s2 2s2 2p6 3s2 3p6

18. COLOURED IONS
A characteristic of transition metals is their ability to form coloured compounds
Theory ) Ions with a d10 (full) or d0 (empty) configuration are colourless
2) Ions with partially filled d-orbitals tend to be coloured
3) This is caused by the ease of transition of electrons between energy levels
4) Energy is absorbed when an electron is promoted to a higher level The frequency of light is proportional to the energy difference
Colorless: Not transition metal
Ions with d10 (full) Cu+,Ag+ Zn2+
d0 (empty) Sc3+
But Ti+4 compounds are white, nevertheless is a transition metal because of Ti+2 and Ti+3 which are colored

19. There are 5 different orbitals of the d variety
3d ORBITALS
There are 5 different orbitals of the d variety xy xz yz
x2-y2 z2

20. COLOURED IONS a solution of copper(II)sulphate is blue because
red and yellow wavelengths are absorbed
blue and green not absorbed
white light