d- and f-Block Elements · Question 10

The pair of lanthanoid ions which are diamagnetic is

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

Which of the following pairs of ions will have same spin only magnetic moment values within the pair? Choose the correct answer from the options given below :

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

Which of the following set of ions act as oxidising agents?

1. Ce4+ and Tb4+
2. La3+ and Lu3+
3. Eu2+ and Yb2+
4. Eu2+ and Tb4+

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