The Lanthanoids
Chapter Name : The D- And F- Block Elements |
Sub Topic Code : 102_12_08_05_04 |
Topic Name : The Lanthanoids |
|
Sub Topic Name : General Characteristics |
|
Introduction
• All the lanthanoids are silvery white soft
metals and tarnish rapidly in air.
• The hardness increases with increasing atomic
number, samarium being steel hard.
• Their melting points range between 1000 to
1200 K but samarium melts at 1623 K
•
They have typical metallic structure and are good
conductors of heat and electricity.
•
Density and other properties change smoothly except
for Eu and Yb and occasionally for Sm and Tm.
•
Many trivalent lanthanoid ions are coloured both in
the solid state and in aqueous solutions.
The lanthanoid ions
other than the f 0 type (La3+ and Ce4+) and
the f 14 type (Yb2+ and Lu3+) are all
paramagnetic.
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 mischmetall 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
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:
• All the lanthanoids are silvery white soft
metals and tarnish rapidly in air.
• The hardness increases with increasing atomic
number, samarium being steel hard.
• Their melting points range between 1000 to
1200 K but samarium melts at 1623 K
•
They have typical metallic structure and are good
conductors of heat and electricity.
•
Density and other properties change smoothly except
for Eu and Yb and occasionally for Sm and Tm.
•
Many trivalent lanthanoid ions are coloured both in
the solid state and in aqueous solutions.
The lanthanoid ions
other than the f 0 type (La3+ and Ce4+) and
the f 14 type (Yb2+ and Lu3+) are all
paramagnetic.
What you learn in Practice:
• All the lanthanoids are silvery white soft
metals and tarnish rapidly in air.
• The hardness increases with increasing atomic
number, samarium being steel hard.
• Their melting points range between 1000 to
1200 K but samarium melts at 1623 K
•
They have typical metallic structure and are good
conductors of heat and electricity.
•
Density and other properties change smoothly except
for Eu and Yb and occasionally for Sm and Tm.
•
Many trivalent lanthanoid ions are coloured both in
the solid state and in aqueous solutions.
The lanthanoid ions
other than the f 0 type (La3+ and Ce4+) and
the f 14 type (Yb2+ and Lu3+) are all
paramagnetic.