Lanthanoids Flashcards
(61 cards)
What are the two series that make up the f-block?
Lanthanoids and actinoids
The f-block consists of the fourteen lanthanoids following lanthanum and the fourteen actinoids following actinium.
Which element is usually included in discussions of the lanthanoids?
Lanthanum
Lanthanum closely resembles the lanthanoids and is often represented by the general symbol Ln.
What general symbol is often used for lanthanoids?
Ln
Ln is used to represent the series of lanthanoids.
How do lanthanoids compare to ordinary transition elements?
Lanthanoids resemble one another more closely
They have only one stable oxidation state, which allows for examination of small changes in size and nuclear charge.
What complicates the chemistry of actinoids?
Wide range of oxidation states and radioactivity
The complexity arises from the variety of oxidation states and the special problems posed by their radioactivity.
What is the oxidation state characteristic of lanthanoids?
One stable oxidation state
This allows for a clearer comparison among the lanthanoids.
What are the key features of the actinoids’ chemistry?
Complicated due to oxidation states and radioactivity
The actinoids exhibit a wide range of oxidation states and their radioactivity complicates their study.
What is the common electronic configuration of the atoms mentioned?
6s
Atoms have variable occupancy of the 4f level.
What is the most stable oxidation state of all the lanthanoids?
Tripositive ions
This oxidation state has electronic configurations of the form 4f^n (n = 1 to 14 with increasing atomic number).
The electronic configurations of tripositive ions of lanthanoids are of the form _______.
4f^n (n = 1 to 14)
The variable occupancy corresponds to increasing atomic number.
What is the lanthanoid contraction?
The lanthanoid contraction is the overall decrease in atomic and ionic radii from lanthanum to lutetium in the lanthanoid series.
Q: What causes the lanthanoid contraction?
The lanthanoid contraction is caused by imperfect shielding of the 4f electrons, which leads to an increase in effective nuclear charge experienced by the outer electrons.
Q: How does lanthanoid contraction affect the M³⁺ ions?
The decrease in size of M³⁺ ions is fairly regular across the series due to the lanthanoid contraction
Q: How does lanthanoid contraction affect the M³⁺ ions?
The decrease in size of M³⁺ ions is fairly regular across the series due to the lanthanoid contraction
Q: What happens to nuclear charge across the lanthanoid series?
A: The nuclear charge increases along the lanthanoid series, contributing to the contraction in size.
Which elements exhibit almost identical radii due to the lanthanoid contraction?
Back:
Zirconium (Zr) and Hafnium (Hf) exhibit almost identical radii due to the lanthanoid contraction.
What series of elements does the lanthanoid contraction affect?
Back:
The lanthanoid contraction affects the radii of the members of the third transition series, making them similar to the corresponding members of the second series.
How does the lanthanoid contraction influence chemical separation?
Back:
The lanthanoid contraction makes the separation of elements with similar radii, like Zr and Hf, more difficult in natural processes.
Predominant oxidation states of Lanthanoids
La+² , La +³
Ocassionally __ and ___ in solution or solids occured
+2 and +4
Irregular in ionisation enthalpy arise due to
Extra stability of half filled
Empty
Completely filled f orbitals
Ce +⁴ configuration is ______and its strong oxidant or reductant reverting +³ common state
It can oxidise ____
Water
Ce+⁴ can oxidise water it’s good ___ agent
Analytical agent
Pr Nd Tb Dy exhibit ___ ox state only in Oxides MO²
+4
