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प्रश्न
The second and third rows of transition elements resemble each other much more than they resemble the first row. Explain why?
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उत्तर
Due to lanthanide contraction, the atomic radii of the second and third row transition elements are almost same. So, they resemble each other much more as compared to first row elements.
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संबंधित प्रश्न
Account for the following:
Zn is not considered as a transition element.
Out of Mn3+ and Cr3+, which is more paramagnetic and why ?
(Atomic nos. : Mn = 25, Cr = 24)
Which metal in the first series of transition metals exhibits +1 oxidation state most frequently and why?
How would you account for the following?
Transition metals and their compounds act as catalysts.
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 |
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?
A solution of \[\ce{KMnO4}\] on reduction yields either a colourless solution or a brown precipitate or a green solution depending on pH of the solution. What different stages of the reduction do these represent and how are they carried out?
Match the solutions given in Column I and the colours given in Column II.
| Column I (Aqueous solution of salt) |
Column II (Colour) |
| (i) \[\ce{FeSO2.7H2O}\] | (a) Green |
| (ii) \[\ce{NiCl2.4H2O}\] | (b) Light pink |
| (iii) \[\ce{MnCl2.4H2O}\] | (c) Blue |
| (iv) \[\ce{CoC12,6H2O}\] | (d) Pale green |
| (v) \[\ce{Cu2 Cl2}\] | (e) Pink |
| (f) Colourless |
A metallic ion 'M' reacts with chloride ion to form white precipitate which is readily soluble in aqueous ammonia. Identify 'M'?
Catalytic hydrogenation of benzene gives
Which of the following statements is not correct?
The basic character of transition metals monoxide follow the order.
Which of the following ions has the maximum magnetic moment?
The electrode potential of M2+/M of 3d-series elements shows the positive value for ______.
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`]
In order to protect iron from corrosion, which one will you prefer as a sacrificial electrode, Ni or Zn? Why? (Given standard electrode potentials of Ni, Fe and Zn are -0.25 V, -0.44 V and -0.76 V respectively.)
Write the ionic equation for reaction of KI with acidified KMnO4.
A coordination compound has the formula \[\ce{CoCl3.4NH3}\]. It precipitates silver ions as AgCl and its molar conductance corresponds to a total of two ions.
Based on this information, answer the following question:
- Deduce the structural formula of the complex compound.
- Write the IUPAC name of the complex compound.
- Draw the geometrical isomers of the complex compound.
Describe the oxidising action of potassium dichromate and write the ionic equation for its reaction with H2S.
