1
###
Larger number of oxidation states are exhibited by the actinoids

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

- 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 reactive nature of the actinoids than the lanthanoids
- 4f orbitals more diffused than the 5f orbitals

2
###
The lanthanide contraction is responsible for the fact that

The lanthanide contraction is responsible for the fact that

- Zr and Hf have about the same radius
- Zr and Y have about the same radius
- Zr and Zn have the same oxidation state
- Zr and Nb have similar oxidation state

3
###
A reduction in atomic size with increase in atomic number

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

- radioactive series
- d block
- high atomic masses
- f block

4
###
The number of d electrons retained in Fe2+ ions is

The number of d electrons retained in Fe^{2+} (At. no. Fe = 26) ions is

- 3
- 4
- 5
- 6

5
###
The color of KMnO4 is due to

The color of KMnO_{4} is due to

- d – d transition
- L → M charge transfer transition
- σ – σ* transition
- M → L charge transfer transition

6
###
The pair having the same magnetic moment is

The pair having the same magnetic moment is:

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

- [Cr(H
_{2}O)_{6}]^{2+}and [Fe(H_{2}O)6]^{2+} - [Mn(H
_{2}O)_{6}]^{2+}and [Cr(H_{2}O)6]^{2+} - [CoCl
_{4}]^{2–}and [Fe(H_{2}O)_{6}]^{2+} - [Cr(H
_{2}O)_{6}]^{2+}and [CoCl_{4}]^{2–}

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