Give reasons:

Actinoids show irregularities in their electronic configurations.

Name the members of the lanthanide series which exhibit +4 oxidation states and those which exhibit +2 oxidation state. Try to correlate this type of behaviour with the electronic configuration of these elements.

Compare the chemistry of actinoids with that of lanthanoid with reference to

a) Electronic configuration

b) Oxidation states

c) Chemical Reactivity

The chemistry of the actinoid elements is not so smooth as that of the lanthanoids. Justify this statement by giving some examples from the oxidation state of these elements.

Compare the chemistry of actinoids with that of the lanthanoids with special reference to:

(i) electronic configuration (iii) oxidation state

(ii) atomic and ionic sizes and (iv) chemical reactivity.

A. Account for the following:

(i) Transition metals form a large number of complex compounds.

(ii) The lowest oxide of transition metal is basic whereas the highest oxide is amphoteric or acidic.

(iii) E° value for the Mn³⁺/Mn²⁺ couple is highly positive (+1.57 V) as compare to Cr³⁺/Cr²⁺.

B. Write one similarity and one difference between the chemistry of lanthanoid and actinoid elements.

OR

A. (i) How is the variability in oxidation states of transition metals different from that of the p-block elements?

(ii) Out of Cu⁺ and Cu²⁺, which ion is unstable in aqueous solution and why?

(iii) Orange colour of Cr₂O₇^2– ion changes to yellow when treated with an alkali. Why?

B. Chemistry of actinoids is complicated as compared to lanthanoids. Give two reasons.

Write the main product(s) in each of the following reactions:

(i)

(ii)

(iii)

Give reasons:

Actinoids show irregularities in their electronic configurations.