An element among the following that exhibits the maximum oxidation state is:

1. Cr

2. Mn

3. Fe

4. V

Which of the following is a coloured and paramagnetic compound?

1. CuF₂

2. K₂Cr₂O₇

3. $KMn{O}_4$

4. K₄[Fe(CN)₆]

Which of the following elements can combine with chlorine to form more than one binary compound?

1. Zn

2. K

3. Ca

4. Fe

A set of ions among the following that have a 3d² electronic configuration is:

1. ${\mathrm{Ti}}^{+},{\mathrm{V}}^{4+},{\mathrm{Cr}}^{6+},{\mathrm{Mn}}^{7+}$

2. ${\mathrm{Ti}}^{4+},{\mathrm{V}}^{3+},{\mathrm{Cr}}^{2+},{\mathrm{Mn}}^{3+}$

3. ${\mathrm{Ti}}^{2+},{\mathrm{V}}^{3+},{\mathrm{Cr}}^{4+},{\mathrm{Mn}}^{5+}$

4. ${\mathrm{Ti}}^{3+},{\mathrm{V}}^{2+},{\mathrm{Cr}}^{3+},{\mathrm{Mn}}^{4+}$

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

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

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:

1. s-orbital is becoming more and more half-filled.

2. f-orbital is becoming more and more half-filled.

3. d-orbital is becoming more and more half-filled.

4. p-orbital is becoming more and more half-filled.

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

1. ${\mathrm{VO}}_3^{-}$

2. ${\mathrm{CrO}}_4^{2-}$

3. ${\mathrm{MnO}}_4^{-}$

4. All of the above.

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