F Block Elements Properties Uses

Actinoids exhibit more oxidation states than lanthanoids. The main reason for this is:

1.	More energy difference between 5f and 6d orbitals than that between 4f and 5d orbitals
2.	Greater metallic character of the lanthanoids than that of the corresponding actinoids
3.	The lesser energy difference between 5f and 6d orbitals than that between 4f and 5d orbitals
4.	More active nature of the actinoids

Diamagnetic lanthanoid ion among the following is:
(At nos. Ce = 58, Sm = 62, Eu = 63, Yb = 70)
1. Sm²⁺
2. Eu²⁺
3. Yb²⁺
4. Ce²⁺

Gadolinium belongs to 4f series. It’s atomic number is 64. Which of the following is the correct electronic configuration of gadolinium?

1.		2.
3.		4.

Identify the incorrect statements related to lanthanons:

1.	Europium shows +2 oxidation state.
2.	The basicity decreases as the ionic radius decreases from Pr to Lu.
3.	All the lanthanons are much more reactive than aluminium.
4.	Ce+4 solutions are widely used as oxidizing agents in volumetric analysis.

The incorrect statement among the following is:

1.	Lanthanoids are good conductors of heat and electricity.
2.	Actinoids are highly reactive metals, especially when finely divided.
3.	Actinoid contraction is greater for element to element than Lanthanoid contraction.
4.	Most of the trivalent Lanthanoid ions are colourless in the solid-state.

Gadolinium has a low value of third ionisation enthalpy because of:

1.	High basic character	2.	Small size
3.	High exchange enthalpy	4.	High electronegativity

The pair of lanthanoid ions, consisting of elements which are diamagnetic, is:

1.	Ce3+ and Eu2+	2.	Gd3+ and Eu3+
3.	Pm3+ and Sm3+	4.	Ce4+ and Yb2+