1. Chapter 3 Notes: First-row d-block Elements
Chapter 13.1: The transition elements have characteristic properties; these properties are related to their all having incomplete d sub-levels
Chapter 3 Notes: First-row d-block Elements

2. Important terms for this section
Magnetic properties
Diamagnetism
Paramagnetism
Ferromagnetism
Domains
General notes about first-row d-block elements
Tends to have a “lull” in periodic patterns
Have similar chemical and physical properties
Complex ions
Coordination number
Coordinate bond
Polydentate ligands
Chelating agents
Catalyst
Haber process
Contact process

3. Atomic Radii The electron configurations
of d-block elements are very similar
Small increase of ENC going across period
The increase of the 3d electrons shield 4s from interacting with protons
Thus, atomic radii is relatively similar across period
This explains the ability of metals to form alloys (solutions/mixtures of metals)
Atoms of 1 d-block metal can often replace another and still keep the structure

4. Physical properties All metals
High electrical and thermal conductivity
High melting point
Malleable
High tensile strength – hold large loads w/o breaking
Ductile
Iron, cobalt, and nickel are ferromagnetic
Strongest magnetism (discussed section 13.2)

5. Physical properties explained
Metallic bonding (chapter 4)
Sea of delocalized electrons
Holds metal lattice together
Strong metallic bonds
High electrical conducivity
Small atomic radii
Higher density than K and Ca

6. Definition of transition metal (TM)
Elements whose atoms have an incomplete d sub-level shell, or which can form cations with an incomplete d sub-shell.
Which elements are not transition metals in the 4th row?
Potassium, Calcium, Zinc, Gallium  Krypton
Zinc
Does not typically form colored compounds
Shows only 2+ oxidation state in compounds

7. Chemical properties In general:
Form compounds with more than one oxidation number
Form numerous complex ions
Form colored compounds
Act as catalysts when elements or compounds

8. Variable oxidation numbers
The big jump Ca forms from +2 to +3 means this is energetically unstable
Ti is more gradual, so can form +2, +3, +4 then a jump occurs so will not form +5

9. Variable oxidation numbers
Various oxidation states: the ones in blue are the most common

10. Variable oxidation numbers
All TMs have +2 and +3
+3 is more common for early TMs and +2 for later due to the increase in ENC (and electronegativity)
Max oxidation state increases +1 until Mn at +7 then decreases -1
This is due to use of 4s and 3d electrons
Oxidation states above +3 show covalent character
Higher + charge pulls more on the electrons of anion
Higher oxid. state tend to be oxidizing agents

11. Complex ions Coordinate bond also called dative bond
A lone pair of electrons is used to form cov. bond
High charge density in solution, TM attract H2O molecules (or other molecules/ions with lone pairs of e-) called ligands

12. Complex ions
Number of bonds attached to the central metal ion = coordination number
Number and type of ligand can change the color
[Cu(H2O)6]2+ + HCl 
[Cu(Cl)4]2- + NH3 
[Cu(H2O)2(NH3)4]2+

13. Complex ions

14. Polydentate ligands – chelating agents
Polydentate: able to provide multiple lone pairs for ligand bonding
Chelate: complex having at least 1 polydentate ligand
EDTA4- can take the place of 6 monodentate ligands
Important in foods
Binds TM ions
To Inhibit oxid. RXNs :

15. TM and their ions as catalysts
Catalyst: increases rate of RXN by lowering activation energy
Two types of TM catalysts
Homogeneous
Heterogeneous

16. Heterogeneous TM catalysts
Heterogeneous catalyst: the catalyst is in a different state from the reactants
Haber process: used to produce ammonia
Uses Fe solid powder as a catalyst
N2(g) + 3H2(g)  2NH3(g)
Contact Process: used to produce SO3 for sulfuric acid production
V2O5 solid (pellets) used as a catalyst
2SO2(g) + O2(g)  SO3(g)
Easily removed via filtration – preferred for industry

17. Homogeneous TM catalysts
Homogeneous catalysts: catalyst is in same state as the reactants
Fe2+ in heme for oxygen transport
Co3+ in Vitamin B12

18. Magnetic properties of TMs and their compounds
Unpaired electrons can act like small magnets
When aligned, these can have a variety of magnetic properties
This is determined by placing in an external magnetic field
3 types of magnetism
Diamagnetic
Paramagnetism
Ferromagnetism

19. Diamagnetism
Diamagnetic – property of all materials with weak magnetism
Most materials are diamagnetic
Orbital motion of electrons produce magnetic fields that oppose external magnetic fields
Zinc is diamagnetic (no unpaired e-)

20. Paramagnetism
Occurs with substances which have unpaired electrons and is stronger than diamagnetism
Produces magnetization proportional to the applied field (and in the same direction)
Is a property of single atoms or ions with unpaired, spinning electrons
Increases as number of unpaired e- increases then reaches a max at Cr then decreases

21. Ferromagnetic
Largest effect sometimes producing effects larger than the applied field
Occurs when there is a long range ordering of unpaired e-
Fe, Co and Ni
With many atoms, the large number of unpaired e- can line up in domains
Become more ordered when mag. field applied
Magnetism remains after field removed