Write the formula of an oxo-anion of Manganese (Mn) in which it shows the oxidation state equal to its group number.

Write the formula of an oxo-anion of Chromium (Cr) in which it shows the oxidation state equal to its group number.

Assign the reason for the following : Copper (I) ion is not known in aqueous solution.

Explain the following : (i) The enthalpies of atomization of transition metals are quite high. (ii) The transition metals and many of their compounds act as good catalysts.

Explain the following observation : Most of the transition metal ions exhibit characteristic colour in aqueous solution.

How would you account for the following ? Many of the transition elements are known to form interstitial compounds.

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

What is meant by ‘disproportionation’ ? Give an example of a disproportionation reaction in aqueous solution.

Suggest reasons for the following features of transition metal chemistry : (i) The transition metals and their compounds are usually paramagnetic. (ii) The transition metals exhibit variable oxidation states.

Complete the following chemical equations : (i) MnO₄⁻(aq) + S₂O₃²⁻(aq) + H₂O(l) → (ii) Cr₂O₇²⁻(aq) + Fe²⁺(aq) + H⁺(aq) →

Complete and balance the following chemical equations: (a) Fe²⁺ + MnO₄⁻ + H⁺ → (b) MnO₄⁻ + H₂O + I⁻ →

In the following ions: Mn³⁺, V³⁺, Cr³⁺, Ti⁴⁺ (Atomic no: Mn = 25, V = 23, Cr = 24, Ti = 22) (a) Which ion is most stable in an aqueous solution? (b) Which ion is the strongest oxidizing agent? (c) Which ion is colourless? (d) Which ion has the highest number of unpaired electrons?

Explain the following observations: (i) Copper atom has completely filled d orbitals (3d¹⁰) in its ground state, yet it is regarded as a transition element. (ii) Cr²⁺ is a stronger reducing agent than Fe²⁺ in aqueous solution.

Name the following : (i) A transition metal which does not exhibit variation in oxidation state in its compounds. (ii) A compound where the transition metal is in the +7 oxidation state. (iii) A member of the lanthanoid series which is well known to exhibit +4 oxidation state. (iv) Ore used in the preparation of Potassium dichromate.

Explain why : (i) E° for Mn³⁺/Mn²⁺ couple is more positive than that for Fe³⁺/Fe²⁺. (At. Nos. Mn = 25, Fe = 26). (ii) Ce³⁺ can be easily oxidized to Ce⁴⁺. (At. No.Ce = 58).