Transition Metal Chemistry
Here are six examples of the importance of transition metals in our lives:
➞ Iron (Fe) - used to make steel; complexes of Fe provide transport and storage of O2 in living organisms.
➞ Copper (Cu) - electrical wiring; water pipes; plays a crucial role in the respiratory cycle.
➞ Titanium (Ti) - in paint.
➞ Silver (Ag) - in photographic paper.
➞ Zinc (Zn) - found in 150 biomolecules such as Vitamin B12 d
Properties of Transition Metals
The list of physical and chemical properties of transition metals is endless.
So, we'll just list the 4 main properties you should know here...
1. Unlike other elements, transition metals shows similar properties both down a group and across a period.
Because across a period, transition metals add inner core electrons to inner d- and/or f-orbitals which don't participate as easily as s- and p-electrons.
All other types of elements add electrons to outer s- and/or p-orbitals across a period.
2. Lustrous (shiny).
3. Good conductors of electricity.
➞ because of the delocalized electron model for metallic bonding.
➞ silver is the best conductor; copper (cheaper) is a close second.
4. Despite visible similarities, transition metals have varying chemical and physical properties:
ex: melting point / boiling point
➞ Tungsten (W) melts at 3400°C, yet mercury (Hg) is a liquid at 25°C.
➞ Fe and Ti are used in structures, but Cu, Ag, and Au are malleable and ductile (soft).
Formation of Complex Ions
When forming ionic compounds (with nonmetals or polyatomic anions), transition metals exhibit typical characteristics:
a. multiple oxidation states (ex: Fe2+ vs. Fe3+).
b. cations are often complex ions.
Wait a second... What's a complex ion??
What's a Complex Ion?
complex ions = species where the transition metal is surrounded by ligands.
ligands = molecules or ions that act as Lewis bases (electron pair donor).
Here's an example of a complex ion:
c. most compounds are colored because the transition metal ion in the complex ion absorbs visible light and we see the the complimentary color ( VY | BO | GR ).
d. many transition metal compounds are paramagnetic (contain unpaired electrons).
Ready for the next video?...
Let's continue with SECTION 18 - Transition Metals and Coordination Chemistry by discussing: