1. Unless otherwise stated, all images in this file have been reproduced from:
Blackman, Bottle, Schmid, Mocerino and Wille,      Chemistry, 2007 (John Wiley)      ISBN:

2. CHEM1002 [Part 2] Dr Michela Simone Lecturer
BSc (I Hons), MSc, D.Phil. (Oxon), MRSC, MRACI
Weeks 8 – 13
Office Hours: Monday 3-5, Friday 4-5
Room: 412A (or 416)
Phone:
It is a good idea if all lecturers can make an appearance for the first lecture.
Remind students we are IT for the rest of the semester.
DEMOS for this lecture:
EXP 2.3: “Charles law (2.3),
EXP 2.1 “CO2 density (2.1)

3. Summary of Last Lecture
Complexes II
For octahedral complexes with formulae [MX2Y4], cis and trans geometrical isomers are possible
For square planar complexes with formulae [MX2Y2], cis and trans geometrical isomers are possible
For octahedral complexes with bidentate ligands, optical isomerism is also possible
Metal complex formation can greatly increase solubility

4. Complexes III Lecture 14 Transition Metals Electron Configuration
Oxidation States
Colours
Magnetism
Blackman Chapter 13, Sections 13.4 and 13.7
Lecture 15
Metals in Biological Processes
Essential Elements
Toxic Elements
Medicinal Uses
Blackman Chapter 13

5. Transition (or d-block) Metals

6. Electronic Configurations of Atoms
In 4th row, 4s and 3d orbitals are available for electrons
There is one 4s orbital: it can accommodate 2 electrons
There are five 3d orbitals: each can accommodate 2 electrons, giving a total of 10 electrons
Fill 4s then 3d
energy 3d 4s

7. Atomic Configurations
Fill 4s then 3d
Group number gives number of valence electrons
Electronic configurations:
K: group 1 so [Ar](4s)1(3d)0
Sc: group 3 so [Ar](4s)2(3d)1
Mn: group 7 so [Ar](4s)2(3d)5
Ni: group 10 so [Ar](4s)2(3d)8
Zn: group 12 so [Ar](4s)2(3d)10
[Ar](4s)x(3d)y
where x + y = group

8. Electronic Configurations of Cations
Fill 3d only
Group number gives number of valence electrons
Cation has (group number – oxidation number) electrons
Mn7+: group 7 and oxidation number 7 so has:
(7 – 7) = 0 electrons: [Ar](3d)0
Mn2+: group 7 and oxidation number 2 so has
(7 – 2) = 5 electrons: [Ar](3d)5
Ni2+: group 10 and oxidation number 2 so has
(10 – 2) = 8 electrons: [Ar](3d)8
Ni3+: group 10 and oxidation number 3 so has
(10 – 3) = 7 electrons: [Ar](3d)7
(4s always empty!)
Demo Fe/Mn reaction

9. Electronic Configurations of Cations
To minimize repulsion between electrons, they occupy d-orbitals singly with parallel spins until they have to pair up:
Mn2+: [Ar](3d)5 3d
Ni2+: [Ar](3d)8 3d
Demo Fe/Mn reaction
If the metal cation has unpaired electrons, the complex will be attracted to a magnet: paramagnetic

10. Aqueous Oxoanions of Transition Metals
One of the most characteristic chemical properties of these elements is the occurrence of multiple oxidation numbers, often associated with different colours.
Ion Ox. No. Colour
VO yellow
VO green
V blue
V violet

11. Colourful Complexes
Aqueous solutions of the Co(III) complexes (from left to right): [Co(NH3)5OH2]3+, [Co(NH3)6]3+, trans-[Co(en)2Cl2]+, [Co(en)2O2CO]+ and [Co(NH3)5Cl]2+.
All contain Co(III): colour influenced by the ligand
Blackman, Bottle, Schmid, Mocerino & Wille (2007). Wiley & Sons: FIGURE Aqueous solutions of the Co(III) complexes: (from left to right) [Co(NH3)5OH2]3+,
[Co(NH3)6]3+, trans-[Co(en)2Cl2]+, [Co(en)2O2CO]+ and [Co(NH3)5Cl]2+. As the metal ion is the same in
all cases, the variety of colours arises from the different ligands surrounding the Co(III) ion.

12. Absorbed and Observed Colours
Unless the d-orbitals are empty, half full or full, electrons can be excited from one d-orbital to another: absorption of light which we see as colour

13. Summary: Complexes II Complete the worksheet
Learning Outcomes - you should now be able to:
Complete the worksheet
Work out the electron configurations of atoms and cations
Work out the number of unpaired electrons
Answer review problems in Blackman
Next lecture:
The Biological Periodic Table

14. Practice Examples
How many d-electrons and how many unpaired electrons are there in the following complexes?
K2[NiCl4]
[Co(en)3]Cl3
[CrCl2(OH2)4]+
K2[Zn(OH)4]
[PtCl2(NH3)2]
2. Consider the compound with formula [CoCl2(NH3)4]Br2H2O
(i) Write the formula of the complex ion.
(ii) Write the symbols of the ligand donor atoms.
(iii) What is the d electron configuration of the metal ion in this complex?