Larger number of oxidation states are exhibited by the actinoids than those by the lanthanoids, the main reason being

• 4f orbitals more diffused than the 5f orbitals

• lesser energy difference between 5f and 6d than between 4f and 5d orbitals

• more energy difference between 5f and 6d than between 4f and 5d orbitals

• more energy difference between 5f and 6d than between 4f and 5d orbitals

Identify the incorrect statement among the following –

• d-Block elements show irregular and erratic chemical properties among themselves

• La and Lu have partially filled d orbitals and no other partially filled orbitals

• The chemistry of various lanthanoids is very similar

• The chemistry of various lanthanoids is very similar

The actinoids exhibits more number of oxidation states in general than the lanthanoids. This is because

• the 5f orbitals are more buried than the 4f orbitals

• there is a similarity between 4f and 5f orbitals in their angular part of the wave function

• the actinoids are more reactive than the lanthanoids

• the actinoids are more reactive than the lanthanoids

The stability of dihalides of Si, Ge, Sn and Pb increases steadily in the sequence

• GeX₂ << SiX₂ << SnX₂<< PbX₂

• SiX₂ << GeX₂ << PbX₂<< SnX₂

• SiX₂ << GeX₂ << SnX₂<< PbX₂

• SiX₂ << GeX₂ << SnX₂<< PbX₂

A metal, M forms chlorides in it's +2 and +4 oxidation states. Which of the following statements about these chlorides is correct?

• MCl₂ is more volatile than MCl₄

• MCl₂ is more soluble in anhydrous ethanol than MCl₄

• MCl₂ is more ionic than MCl₄

• MCl₂ is more ionic than MCl₄

Lanthanoid contraction is caused due to

• the appreciable shielding on outer electrons by 4f electrons from the nuclear charge

• the appreciable shielding on outer electrons by 5d electrons from the nuclear charge

• the same effective nuclear charge from Ce to Lu

• the same effective nuclear charge from Ce to Lu

17.

The oxidation state of chromium in the final product formed by the reaction between KI and acidified potassium dichromate solution is

• +4

• +6

• +2

• +2

The lanthanide contraction is responsible for the fact that

• Zr and Y have about the same radius

• Zr and Nb have similar oxidation state

• Zr and Hf have about the same radius

• Zr and Hf have about the same radius

Which of the following factors may be regarded as the main cause of lanthanide contraction?

• Poor shielding of one of 4f electron by another in the subshell

• Effective shielding of one of 4f electrons by another in the subshell

• Poorer shielding of 5d electrons by 4f electrons

• Poorer shielding of 5d electrons by 4f electrons

Cerium (Z = 58) is an important member of the lanthanoids. Which of the following statements about cerium is incorrect?

• The common oxidation states of cerium are +3 and +4

• Cerium (IV) acts as an oxidizing agent

• The +4 oxidation state of cerium is not known in solutions

• The +4 oxidation state of cerium is not known in solutions