The general electronic configuration of lanthanoids is:

1. (n – 2) f ^1–14 (n – 1) s² p⁶ d^0–1 ns²

2. (n – 2) f ^10–14 (n – 1) d^0–1 ns²

3. (n – 2) f ^0–14 (n – 1) d¹⁰ ns²

4. (n – 2) d^0–1 (n – 1) f ^1–14 ns²

Zn gives H₂ gas with H₂SO₄ and HCl but not with HNO₃ because:
 

An incorrect statement among the following is :

The catalytic activity of transition metals is due to:

The basic character of the transition metal monoxides follows the order:
(Atomic nos. Ti = 22, V = 23, Cr = 24, Fe = 26)

The correct order of ionic radii of Y³⁺, La³⁺, Eu³⁺, and Lu³⁺ is:

(Atomic nos. Y = 39, La = 57, Eu = 63, Lu = 71)

1. Y³⁺ < La³⁺ < Eu³⁺ < Lu³⁺

2. Y³⁺ < Lu³⁺ < Eu³⁺ < La³⁺

3. Lu³⁺ < Eu³⁺ < La³⁺ < Y³⁺

4. La³⁺ < Eu³⁺ < Lu³⁺ < Y³⁺

Mn²⁺ compounds are more stable than Fe²⁺ compounds towards oxidation in their +3 state because :

The +2 oxidation state becomes more stable in the first half of the first-row transition elements with increasing atomic number because:

The oxo metal anions of the 3d series in which the metal exhibits an oxidation state equal to its group number is /are:

The consequence(s) of lanthanoid contraction is/are :