PUC Science 2nd PUC Class 12 - Karnataka Board PUC Question Bank Solutions

To what extent do the electronic configurations decide the stability of oxidation states in the first series of the transition elements? Illustrate your answer with examples.

What may be the stable oxidation state of the transition element with the following d electron configurations in the ground state of its atom?

3d³

What are the characteristics of the transition elements and why are they called transition elements? 

Which of the d-block elements may not be regarded as the transition elements?

In what way is the electronic configuration of the transition elements different from that of the non-transition elements?

How is the variability in oxidation states of transition metals different from that of the non-transition metals? Illustrate with examples.

How is the variability in oxidation states of transition metals different from that of the non-transition metals? Illustrate with examples.

Describe the oxidising action of potassium dichromate and write the ionic equation for its reaction with iodide.

For M²⁺/M and M³⁺/M²⁺ systems, the E^Θ values for some metals are as follows:

Use this data to comment upon:

The stability of Fe³⁺ in acid solution as compared to that of Cr³⁺ or Mn³⁺.

Predict which of the following will be coloured in the aqueous solution?

Ti³⁺, V³⁺, Cu⁺, Sc³⁺, Mn²⁺, Fe³⁺ and Co²⁺. Give reasons for each.

Compare the stability of +2 oxidation state for the elements of the first transition series.

How would you account for the following:

Of the d⁴ species, Cr²⁺ is strongly reducing while manganese (III) is strongly oxidising.

How would you account for the following:

Cobalt (II) is stable in aqueous solutions, but in the presence of complexing reagents, it is easily oxidised.

How would you account for the following: 

The d¹ configuration is very unstable in ions.

What is meant by ‘disproportionation’? 

Which metal in the first series of transition metals exhibits +1 oxidation state most frequently and why?

Calculate the number of unpaired electrons in the following gaseous ions:

Mn³⁺, Cr³⁺, V³⁺ and Ti³⁺. Which one of these is the most stable in an aqueous solution?

What are alloys?

What are inner transition elements?

Use Hund’s rule to derive the electronic configuration of Ce³⁺ ion and calculate its magnetic moment on the basis of ‘spin-only’ formula.