The electronic configurations of Eu (Atomic no. 63), Gd (Atomic no. 64), and Tb (Atomic no. 65) are, respectively:
 

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

2. [Xe] 4f⁶ 5d¹ 6s², [Xe] 4f⁷5d¹ 6s², and [Xe]4f⁸ 5d¹ 6s²

3. [Xe] 4f⁷ 6s², [Xe]4f⁷ 5d¹ 6s², and [Xe] 4f⁹ 6s²

4. [Xe] 4f⁷ 6s², (Xe]4f⁸ 6s², and [Xe]4f⁸ 5d¹ 6s²

Which of the following statements is false? 

A gas that can readily decolorize an acidified KMnO₄ solution is:

1. ${\mathrm{SO}}_2$

2. ${\mathrm{NO}}_2$

3. ${\mathrm{P}}_2{\mathrm{O}}_5$

4. ${\mathrm{CO}}_2$

The ionization potential values of d-block elements as compared to the ionization potential values of f-block elements are:

Which one of the following is a diamagnetic ion?

Which of the following statements is false? 

An element that does not show variable oxidation state is:

A pair among the following that has both coloured ions in the aqueous solution is-
(At. no : Sc =21, Ti = 22, Ni = 28, Cu = 29, Co = 27)

 The increasing order of oxidising power among the following species is :

1. ${{\mathrm{VO}}_2}^{+}< {\mathrm{Cr}}_2{{\mathrm{O}}_7}^{2- }< {{\mathrm{MnO}}_4}^{-}$                           

2. ${{\mathrm{VO}}_2}^{+ }< {{\mathrm{MnO}}_4}^{- }< {\mathrm{Cr}}_2{{\mathrm{O}}_7}^{2-}$

3. ${\mathrm{Cr}}_2{{\mathrm{O}}_7}^{2- }< {{\mathrm{VO}}_2}^{+ }< {{\mathrm{MnO}}_4}^{-},$                           

4. ${\mathrm{Cr}}_2{{\mathrm{O}}_7}^{2- }< {{\mathrm{MnO}}_4}^{- }< {{\mathrm{VO}}_2}^{+}$

The values of X, Y, P, and Q are, respectively:
   

1. ${\mathrm{MnO}}_3^{+}$, Mn₂O₇, conc. H₂SO₄, and K₂MnO₄

2. K₂MnO₄, conc. H₂SO₄, Mn₂O₇, and ${\mathrm{MnO}}_3^{+}$

3. Na₂CO₃, MnO₂, K₂MnO₄, and Mn₂O₇

4. H⁺, K₂MnO₄, ${\mathrm{MnO}}_3^{+}$, and Mn₂O₇