d and f Block Elements

1

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

  1. Lesser energy difference between 5f and 6d than between 4f and 5d orbitals
  2. More energy difference between 5f and 6d than between 4f and 5d orbitals
  3. More reactive nature of the actinoids than the lanthanoids
  4. 4f orbitals more diffused than the 5f orbitals
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2

The lanthanide contraction is responsible for the fact that

  1. Zr and Hf have about the same radius
  2. Zr and Y have about the same radius
  3. Zr and Zn have the same oxidation state
  4. Zr and Nb have similar oxidation state
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3

A reduction in atomic size with increase in atomic number is a characteristic of elements of

  1. radioactive series
  2. d ­block
  3. high atomic masses
  4. f ­block
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4

The number of d ­electrons retained in Fe2+ (At. no. Fe = 26) ions is

  1. 3
  2. 4
  3. 5
  4. 6
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5

The color of KMnO4 is due to

  1. d – d transition
  2. L → M charge transfer transition
  3. σ – σ* transition
  4. M → L charge transfer transition
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6

The pair having the same magnetic moment is:

[At. No.: Cr = 24, Mn = 25, Fe = 26, Co = 27]

  1. [Cr(H2O)6]2+ and [Fe(H2O)6]2+
  2. [Mn(H2O)6]2+ and [Cr(H2O)6]2+
  3. [CoCl4]2– and [Fe(H2O)6]2+
  4. [Cr(H2O)6]2+ and [CoCl4]2–
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