Assertion (A): | Ionisation enthalpies of early actinoids are lower than for early lanthanoids. |
Reason (R): | Electrons are entering 5f orbitals in actinoids which experience greater shielding from nuclear charge. |
1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
3. | (A) is True but (R) is False. |
4. | (A) is False but (R) is True. |
1. | high basic character | 2. | small size |
3. | high exchange enthalpy | 4. | high electronegativity |
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. |
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.
A pair among the following have nearly the same atomic radii:
(Numbers in the parenthesis are atomic numbers).
1. | The greater metallic character of the lanthanoids than that of the corresponding actinoids. |
2. | More energy difference between 5f and 6d orbitals than that between 4f and 5d orbitals. |
3. | The lesser energy difference between 5f and 6d orbitals than that between 4f and 5d orbitals. |
4. | More active nature of the actinoids. |
Lanthanoid's most common oxidation state is:
1. 2
2. 5
3. 3
4. 4
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 |