d- and f-Block Elements · Question 21

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.

The electronic configuration of Eu (Atomic No. 63), Gd (Atomic No. 64) and Tb (Atomic No. 65) are

1. [Xe]4f6 5d1 6s2, [Xe]4f7 5d1 6s2 and [Xe]4f8 5d1 6s2
2. [Xe]4f7 6s2, [Xe]4f7 5d1 6s2 and [Xe]4f9 6s2
3. [Xe]4f7 6s2, [Xe]4f8 6s2 and [Xe]4f8 5d1 6s2
4. [Xe]4f6 5d1 6s2, [Xe]4f7 5d1 6s2 and [Xe]4f9 6s2

Which one of the following statements related to lanthanoids is incorrect?

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 agent in volumetric analysis.