d- and f-Block Elements · Question 13

The UV-visible absorption bands in the spectra of lanthanoid ions are 'X', probably because of the excitation of electrons involving 'Y'. The 'X' and 'Y', respectively, are :

1. Broad and f orbitals
2. Narrow and f orbitals
3. Broad and d and f orbitals
4. Narrow and d and f orbitals

The oxidation states not shown by Mn in given reaction are : 3MnO42- + 4H+ 2MnO4- + MnO2 + 2H2O Choose the most appropriate answer from the options given below :

1. D and E only
2. B and D only
3. A and B only
4. B and E only

The stability of Cu2+ is more than Cu+ salts in aqueous solution due to -

1. enthalpy of atomization.
2. hydration energy.
3. second ionisation enthalpy.
4. first ionisation enthalpy.

Which of the following statements are INCORRECT? Choose the correct answer from the options given below:

1. B and D only
2. C and D only
3. B and C only
4. A and E only

Gadolinium has a low value of third ionisation enthalpy because of

1. small size
2. high exchange enthalpy
3. high electronegativity
4. high basic character

In the neutral or faintly alkaline medium, KMnO4 oxidises iodide into iodate. The change in oxidation state of manganese in this reaction is from

1. +7 to +4
2. +6 to +4
3. +7 to +3
4. +6 to +5

Decrease in size from left to right in actinoid series is greater and gradual than that in lanthanoid series due to

1. 5f orbitals have greater shielding effect
2. 4f orbitals are penultimate
3. 4f orbitals have greater shielding effect
4. 5f orbitals have poor shielding effect

Given below are two statements : In the light of the above statements, choose the most appropriate answer from the options given below :

1. Statement I is incorrect but Statement II is correct
2. Both Statement I and Statement II are correct
3. Both Statement I and Statement II are incorrect
4. Statement I is correct but Statement II is incorrect

The incorrect statement among the following is :

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

Zr (Z = 40) and Hf (Z = 72) have similar atomic and ionic radii because of :

1. Having similar chemical properties
2. Belonging to same group
3. Diagonal relationship
4. Lanthanoid contraction