(a) Given below are the electrode potential values, E^o for the some of the first row of transition elements:

Explain the irregularities in these values on the basis of electronic structures of atoms.
(b) Complete the following reaction equations:
(i) Cr₂O₇^2-+Sn²⁺+H⁺\(\longrightarrow \) 
(ii) MnO₄^-+Fe²⁺+H⁺\(\longrightarrow \)

Calculate the number of unpaired electrons in following gaseous ions: Mn³⁺, Cr³⁺, V³⁺ and Ti³⁺. Which one of these is the most stable in aqueous solution?

Give examples and suggest reasons for the following features of the transition metal chemistry:
(i) The lowest oxide of transition metal is basic, the highest is amphoteric/acidic.
(ii) A transition metal exhibits highest oxidation state in oxides and fluorides.
(iii) The highest oxidation state is exhibited in oxoanions of a metal.

Write down the number of 3d electrons in each of the following ions: Ti²⁺, V²⁺, Cr³⁺, Mn²⁺, Fe²⁺, Fe³⁺, Co²⁺, Ni²⁺ and Cu²⁺. Indicate how would you expect the five 3d orbitals to be occupied for these hydrated ions (octahedral).

On the basis of Lanthanoid contraction, explain the following:
(i) Nature of bonding in La₂O₃ and Lu₂O₃.
(ii) Trends in the stability of oxo salts of lanthanoids from LA to Lu.
(iii) Stability of the comlexes of lanthanoids.
(iv) Radii of 4d and 5d block elements.
(v) trends in acidic character of lanthanoid oxides.

(a) Answer the following questions:
(i) Which element of the first transition series has highest second ionisation enthalpy?
(ii) Which element of the first transition series has highest third ionisation enthalpy?
(iii) Which element of the first transition series has lowest enthalpy of atomisation?
(b) Identify the metal and justify your answer.
(i) Carbonyl M(CO)₅
(ii) MO₃F

(a) Complete the following chemical equations :
\((i)\ { Cr }_{ 2 }{ O }_{ 7 }^{ 2- }(aq)+{ H }_{ 2 }S(g)+{ H }^{ + }(aq)\longrightarrow \) 
\((ii)\ { Cu }^{ 2+ }(aq)+{ I }^{ - }(aq)\longrightarrow\)
(b) How would you account for the following ?
(i) The oxidizing power of oxoanions is the order : \({ VO }_{ 2 }^{ + }<{ Cr }_{ 2 }{ O }_{ 7 }^{ 2- }<{ MnO }_{ 4 }^{ - }\)
(ii) The third ionization enthalpy of manganese (Z = 25) is exceptionally high.
(iii) Cr²⁺ is stronger reducing agent than Fe²⁺

Complete the following chemical reaction equations:
(i) \(CrO_{ 7 }^{ 2\quad - }(aq)+H_{ 2 }S(g)+H^{ + }(aq)\longrightarrow \) 
(ii) \(CrO_{ 7 }^{ 2\quad - }(aq)+H_{ 2 }S(g)+H^{ + }(aq)\longrightarrow \)
(b) Explain the following observations:
(i) Transition metals form compounds which are usually coloured.
(ii) Transition metals exhibit variable oxidation states.
(iii) The actinoids exhibit a greater range of oxidation states than the lanthanoids.

(i) With reference to structural variability and chemical reactivity, write the differences between lanthanoids and actinoids.
(ii) Name a member of the lanthanoid series which is well known to exhibit +4 oxidation state.
(iii) Complete the following equation:
\(MnO_{ 4 }^{ - }8H^{ + }5e^{ - }\longrightarrow \) 
(iv) Out of \(Mn^{ 3+ }\) and \(Cr^{ 3+ }\) , which is more paramagnetic and why?
(Atomic nos.: Mn = 25, Cr = 24)

(a) Account for the following:
(i) Mn shows the highest oxidation state of +7 with oxygen but with fluorine, it shows the highest oxidation state of +4.
(ii) Zirconium and Hafnium exhibit similar properties.
(iii) Transition metals act as catalysts.
(b) Complete the following equations:
(i) \(2MnO_{ 2 }+4KOH+O_{ 2 }\overset { \Delta }{ \longrightarrow } \) 
(ii) \(Cr_{ 2 }O_{ 7 }^{ 2- }+14H^{ + }+6I^{ - }\longrightarrow \)