The Actinides
Chapter Name : The D- And F- Block Elements |
Sub Topic Code : 102_12_08_06_01 |
Topic Name : The Actinides |
|
Sub Topic Name : Electronic Configurations |
|
Introduction
• The actinoids include the fourteen elements
from Th to Lr.
• All the actinoids are
believed to have the electronic configuration of 7s2 and variable
occupancy of the 5f and 6d subshells]
•
The fourteen electrons are formally added to 5f,
though not in thorium (Z = 90) but from Pa onwards the 5f orbitals are complete
at element 103.
•
The irregularities in the electronic configurations of
the actinoids, like those in the lanthanoids are related to the stabilities of
the f 0, f 7 and f 14 occupancies of the 5f
orbitals.
• Thus, the
configurations of Am and Cm are [Rn] 5f 77s2 and [Rn] 5f 76d17s2.
Although the 5f
orbitals resemble the 4f orbitals in their angular part of the wave-function,
they are not as buried as 4f orbitals and hence 5f electrons can participate in
bonding to a far greater extent.
Pre-Requisites:
Periodic table, elements
Activity:
Actinides are mainly used in nuclear reactors
(eg Uranium) to produce electricity and power
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 |
|---|---|
| Smoke detectors | Smoke detectors use Americium-241 |
Real life uses :
Americium is used in smoke detectors
Places to visit :
kitchen
Practical examples around us
| Examples | Explainations |
|---|---|
| Americium-241 | Americium-241 is used in smoke detectors |
What you learn in Theory:
• The actinoids include the fourteen elements
from Th to Lr.
• All the actinoids are
believed to have the electronic configuration of 7s2 and variable
occupancy of the 5f and 6d subshells]
•
The fourteen electrons are formally added to 5f,
though not in thorium (Z = 90) but from Pa onwards the 5f orbitals are complete
at element 103.
•
The irregularities in the electronic configurations of
the actinoids, like those in the lanthanoids are related to the stabilities of
the f 0, f 7 and f 14 occupancies of the 5f
orbitals.
• Thus, the
configurations of Am and Cm are [Rn] 5f 77s2 and [Rn] 5f 76d17s2.
Although the 5f
orbitals resemble the 4f orbitals in their angular part of the wave-function,
they are not as buried as 4f orbitals and hence 5f electrons can participate in
bonding to a far greater extent.
What you learn in Practice:
• The actinoids include the fourteen elements
from Th to Lr.
• All the actinoids are
believed to have the electronic configuration of 7s2 and variable
occupancy of the 5f and 6d subshells]
•
The fourteen electrons are formally added to 5f,
though not in thorium (Z = 90) but from Pa onwards the 5f orbitals are complete
at element 103.
•
The irregularities in the electronic configurations of
the actinoids, like those in the lanthanoids are related to the stabilities of
the f 0, f 7 and f 14 occupancies of the 5f
orbitals.
• Thus, the
configurations of Am and Cm are [Rn] 5f 77s2 and [Rn] 5f 76d17s2.
Although the 5f
orbitals resemble the 4f orbitals in their angular part of the wave-function,
they are not as buried as 4f orbitals and hence 5f electrons can participate in
bonding to a far greater extent.