(a) Comment on the following tendencies of transition elements of first series:
(i) They exhibit variable oxidation states.
(ii) They easily form alloys.
(iii) They often act as catalyst.
(b) State the different characteristic of actinoids and lanthanoids which places them in f-block elements.
(c) How many unpaired electrons are there in Ni²⁺(aq)?

Account for the following:
(a)    Transition elements have high boiling point and high enthalpy of atomisation.
(b)    Zn, Cd, Hg are normally not regarded as transition elements.
(c)    Transition metals generally form alloys with other transition metals.
(d)    Transition metals form a number of interstitial compounds.
(e)    Ni²⁺ compounds are thermodynamically more stable than Pt²⁺ compounds.

(i) What are inner transition elements? Write their general electronic configuration.
(ii) 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?

Describe the general characteristics of the transition elements with special reference to their tendency to
(i) exhibit paramagnetism, (ii) form complex compounds, (iii) their catalytic behaviour.

What are the transition elements? Write two characteristics of the transition elements ?

How would you account for the following?

Actinoid contraction is greater than lanthanoid contraction.

How would you account for the following?

Transition metals form coloured compounds.

Complete the following equation:

Which metal in the first transition series (3d series) exhibits + 1 oxidation state most frequently and why?

330.

Which of the following cations are coloured in aqueous solutions and why?

 Sc³⁺, V³⁺, Ti⁴⁺, Mn²⁺ (Atomic number Sc = 21, V = 23, Ti = 22, Mn = 25)