S18E1 - Properties of Transition Metals | What is a Complex Ion?

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

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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...

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1.  Unlike other elements, transition metals shows similar properties both down a group and across a period.

➞ Why?

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.

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2.  Lustrous (shiny).

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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.

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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.

ex:  hardness 

➞ Fe and Ti are used in structures, but Cu, Ag, and Au are malleable and ductile (soft).

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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⁺).

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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:

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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 ).

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d.  many transition metal compounds are paramagnetic (contain unpaired electrons).

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Ready for the next video?...

Let's continue with SECTION 18 - Transition Metals and Coordination Chemistry by discussing: 

Electron Configurations and Periodic Trends of Transition Metals...