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प्रश्न
Write the factors which are related to the colour of transition metal ions.
Write the conditions of colour of transition metal ions.
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उत्तर
- Metal ions exhibit the presence of incompletely filled d-orbitals.
- The presence of unpaired electrons in d-orbitals.
- The d-d transition of electrons due to absorption of radiation in the visible region.
- The metal ion in the complex undergoes a type of hybridisation.
- The geometry of the complex containing transition metal ions is described.
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संबंधित प्रश्न
Account for the following:
Cr2+ is a strong reducing agent.
Which of the 3d series of the transition metals exhibits the largest number of oxidation states and why?
Which is a stronger reducing agent, Cr2+ or Fe2+ and why?
Which of the d-block elements may not be regarded as the transition elements?
How would you account for the following:
Of the d4 species, Cr2+ is strongly reducing while manganese (III) is strongly oxidising.
What are inner transition elements?
Comment on the statement that elements of the first transition series possess many properties different from those of heavier transition elements.
How would you account for the following?
Transition metals and their compounds act as catalysts.
An analysis shows that FeO has a non-stoichiometric composition with formula Fe0.95O. Give reason.
Complete and balance the following chemical equations
`Fe^(2+) + MnO_4^(-) + H^+ ->`
Give reasons:
E° value for the Mn3+/Mn2+ couple is much more positive than that for Fe3+/Fe2+.
Transition metals with highest melting point is ____________.
Metallic radii of some transition elements are given below. Which of these elements will have highest density?
| Element | \[\ce{Fe}\] | \[\ce{Co}\] | \[\ce{Ni}\] | \[\ce{Cu}\] |
| Metallic radii/pm | 126 | 125 | 125 | 128 |
Which of the following will not act as oxidising agents?
(i) \[\ce{CrO3}\]
(ii) \[\ce{MoO3}\]
(iii) \[\ce{WO3}\]
(iv) \[\ce{CrO^{2-}4}\]
Although fluorine is more electronegative than oxygen, but the ability of oxygen to stabilise higher oxidation states exceeds that of fluorine. Why?
Although \[\ce{Cr^3+}\] and \[\ce{Co^2+}\] ions have same number of unpaired electrons but the magnetic moment of \[\ce{Cr^3+}\] is 3.87 B.M. and that of \[\ce{Co^2+}\] is 4.87 B.M. Why?
The second and third rows of transition elements resemble each other much more than they resemble the first row. Explain why?
EΘ of Cu is + 0.34V while that of Zn is – 0.76V. Explain.
Reactivity of transition elements decreases almost regularly from Sc to Cu. Explain.
When a chromite ore (A) is fused with sodium carbonate in free excess of air and the product is dissolved in water, a yellow solution of compound (B) is obtained. After treatment of this yellow solution with sulphuric acid, compound (C) can be crystallised from the solution. When compound (C) is treated with KCl, orange crystals of compound (D) crystallise out. Identify A to D and also explain the reactions.
Identify the metal and justify your answer.
Carbonyl \[\ce{M(CO)5}\]
Transition metals can act as catalysts because these can change their oxidation state. How does \[\ce{Fe(III)}\] catalyse the reaction between iodide and persulphate ions?
The element with atomic number 46 belongs to
Which of the following ions has the maximum magnetic moment?
Match List - I with List - II.
| List - I | List - II | ||
| (A) | [Fe(CN)6]3− | (i) | 5.92 BM |
| (B) | [Fe(H2O)6]3+ | (ii) | 0 BM |
| (C) | [Fe(CN)6]4− | (iii) | 4.90 BM |
| (D) | [Fe(H2O)6]2+ | (iv) | 1.73 BM |
Choose the correct answer from the options given below.
Give reason for the following statement:
Physical and chemical properties of the 4d and 5d series of the transition elements are quite similar to expected.
In the ground state of atomic Fe (Z = 26), the spin-only magnetic moment is ______ × 10-1 BM.
(Round off to the nearest integer).
[Given: `sqrt3 = 1.73, sqrt2 = 1.41`]
Which of the following ions has the electronic configuration 3d6?
(Atomic number: Mn = 25, Co = 27, Ni = 28)
Compare the general characteristics of the first series of the transition metals with those of the second and third series metals in the respective vertical columns. Give special emphasis on the following point:
Ionisation enthalpies
The E° value for the Mn2+/Mn2+ couple is more positive than that of Cr3+/Cr2+ or Fe3+/Fe2+ due to the change of:
