An element among the following that shows the maximum number of oxidation states is:

1. Cr

2. Fe

3. Mn

4. V

Match the following aspects with the respective metals:

               Aspects                                    Metal

(a) The metal which reveals a             (i) Scandium
     maximum number of
     oxidation states

(b) The metal although placed           (ii) Copper 
      in 3d block is considered
      not as a transition element

(c) The metal which does not             (iii) Manganese 
     exhibit variable oxidation states

(d) The metal which in +1                   (iv) Zinc 
     oxidation state in aqueous
     solution undergoes
    disproportionation

Select the correct option :

(1) (a)-(i) (b)-(iv) (c)-(ii) (d)-(iii)

(2) (a)-(iii) (b)-(iv) (c)-(i) (d)-(ii)

(3) (a)-(iii) (b)-(i) (c)-(iv) (d)-(ii)

(4) (a)-(ii) (b)-(iv) (c)-(i) (d)-(iii)

Gadolinium (atomic number 64) is an element of the 4f series, Identify the correct electronic configuration of gadolinium from the following options:

\(1. (X e) 4 f^{7} 5 d^{1} 6 s^{2} \)

2. \( (X e) 4 f^{6} 5 d^{2} 6 s^{2}\)

3. \((X e) 4 f^{8} 6 d^{2}\)

4. \((X e) 4 f^{9} 5 s^{1}\)

The magnetic nature of elements depends on the presence of unpaired electrons. Identify the configuration of the transition element, which shows the highest magnetic moment.

Which of the following is the most appropriate reason why zinc does not exhibit variable oxidation states?

A pair of ions that have the same electronic configuration among their constituent species is:

1. \(Sr^{3+}, Cr^{3+}\)
2. \(Fe^{3+}, Mn^{2+}\)
3. \(Fe^{3+}, Co^{3+}\)
4. \(Cr^{3+}, Fe^{3+}\)

Which transition element does not exhibit variable oxidation states?

1. Manganese (\(Mn\))
2. Chromium(\(Cr\))
3. Scandium(\(Sc\))
4. Iron(\(Fe\))