d- and f-Block Elements · Question 19

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

The calculated spin only magnetic moment of Cr2+ ion is?

1. 4.90 BM
2. 5.92 BM
3. 2.84 BM
4. 3.87 BM

Identify the incorrect statement.

1. The transition metals and their compounds are known for their catalytic activity due to their ability to adopt multiple oxidation states and to form complexes.
2. Interstitial compounds are those that are formed when small atoms like H, C or N are trapped inside the crystal lattices of metals.
3. The oxidation states of chromium in CrO42- and Cr2O72- are not the same.
4. Cr2+ (d4) is a stronger reducing agent than Fe2+ (d6) in water.

The manganate and permanganate ions are tetrahedral due to :

1. The -bonding involves overlap of p-orbitals of oxygen with p-orbitals of manganese
2. The -bonding involves overlap of d-orbitals of oxygen with d-orbitals of manganese
3. The -bonding involves overlap of p-orbitals of oxygen with d-orbitals of manganese
4. There is no -bonding

Which one of the following ions exhibits d-d transition and paramagnetism as well?

1. CrO42-
2. Cr2O72-
3. MnO4-
4. MnO42-

The reason for greater range of oxidation states in actinoids is attributed to

1. actinoid contraction
2. 5f, 6d and 7s levels having comparable energies
3. 4f and 5d levels being close in energies
4. the radioactive nature of actinoids.

Which one of the following statements is correct when SO2 is passed through acidified K2Cr2O7 solution?

1. SO2 is reduced.
2. Green Cr2(SO4)3 is formed.
3. The solution turns blue.
4. The solution is decolourised.