The Lanthanoids
Chapter Name : The D- And F- Block Elements |
Sub Topic Code : 102_12_08_05_03 |
Topic Name : The Lanthanoids |
|
Sub Topic Name : Oxidation States |
|
Introduction
•
In the lanthanoids, La(II) and Ln(III) compounds are
predominant species.
•
However, occasionally +2 and +4 ions in solution or in
solid compounds are also obtained.
•
Pr, Nd, Tb and Dy also exhibit +4 state but only in
oxides, MO2.
•
Eu2+ is formed by losing the two s
electrons and its f 7 configuration accounts for the formation of this ion.
•
However, Eu2+ is a strong reducing agent
changing to the common +3 state. Similarly Yb2+ which has f14
configuration is a reductant.
•
TbIV has half-filled f-orbitals and is an
oxidant.
The behaviour of
samarium is very much like europium, exhibiting both +2 and +3 oxidation
states.
Pre-Requisites:
Periodic table, elements
Activity:
•
The best single use of the lanthanoids
is for the production of alloy steels for plates and pipes.
•
Some individual Ln oxides are
used as phosphors in television screens and similar fluorescing surfaces.
A
good deal of mischmetall is used in Mg-based alloy to produce bullets, shell and
lighter flint.
Real Life Question:
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Key Words / FlashCards
| Key Words | Definitions (pref. in our own words) |
|---|---|
| group | Group is the vertical column on the periodic table which contains elements having the similar properties |
Learning aids / Gadgets
| Gadgets | How it can be used |
|---|---|
| A good deal of mischmetal is used in Mg-based alloy to produce bullets, shell and lighter flint. |
Real life uses :
• The best single use of the lanthanoids is for
the production of alloy steels for plates and pipes.
Places to visit :
Garage, TV set
Practical examples around us
| Examples | Explainations |
|---|---|
| • The best single use of the lanthanoids is for the production of alloy steels for plates and pipes. • A good deal of mischmetall is used in Mg-based alloy to produce bullets, shell and lighter flint. • Some individual Ln oxides are used as phosphors in television screens and similar fluorescing surfaces. |
What you learn in Theory:
•
In the lanthanoids, La(II) and Ln(III) compounds are
predominant species.
•
However, occasionally +2 and +4 ions in solution or in
solid compounds are also obtained.
•
Pr, Nd, Tb and Dy also exhibit +4 state but only in
oxides, MO2.
•
Eu2+ is formed by losing the two s
electrons and its f 7 configuration accounts for the formation of this ion.
•
However, Eu2+ is a strong reducing agent
changing to the common +3 state. Similarly Yb2+ which has f14
configuration is a reductant.
•
TbIV has half-filled f-orbitals and is an
oxidant.
The behaviour of
samarium is very much like europium, exhibiting both +2 and +3 oxidation
states.
What you learn in Practice:
•
In the lanthanoids, La(II) and Ln(III) compounds are
predominant species.
•
However, occasionally +2 and +4 ions in solution or in
solid compounds are also obtained.
•
Pr, Nd, Tb and Dy also exhibit +4 state but only in
oxides, MO2.
•
Eu2+ is formed by losing the two s
electrons and its f 7 configuration accounts for the formation of this ion.
•
However, Eu2+ is a strong reducing agent
changing to the common +3 state. Similarly Yb2+ which has f14
configuration is a reductant.
•
TbIV has half-filled f-orbitals and is an
oxidant.
The behaviour of
samarium is very much like europium, exhibiting both +2 and +3 oxidation
states.