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प्रश्न
Comment on the statement that elements of the first transition series possess many properties different from those of heavier transition elements.
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उत्तर
- In the first transition series, lower oxidation states are more stable, while heavier transition elements have higher oxidation states.
- The 5d transition series exhibits higher ionization enthalpy compared to the 3d and 4d transition series.
- M-M bonding is prevalent in heavier transition metals, but less so in the first series.
- The elements in the first transition series do not form complexes with coordination numbers of 7 or 8.
- Elements in the first series can form high or low-spin complexes based on ligand strength, while those in the other series form low-spin complexes regardless of ligand strength.
APPEARS IN
संबंधित प्रश्न
Explain why is Fe3+ more stable than Fe2+?
How would you account for the irregular variation of ionization enthalpies (first and second) in the first series of the transition elements?
Which of the d-block elements may not be regarded as the transition elements?
For M2+/M and M3+/M2+ systems, the E° values for some metals are as follows:
| Cr2+/Cr | −0.9 V |
| Mn2+/Mn | −1.2 V |
| Fe2+/Fe | −0.4 V |
| Cr3/Cr2+ | −0.4 V |
| Mn3+/Mn2+ | +1.5 V |
| Fe3+/Fe2+ | +0.8 V |
Use this data to comment upon:
- The stability of Fe3+ in acid solution as compared to that of Cr3+ or Mn3+ and
- the ease with which iron can be oxidised as compared to a similar process for either chromium or manganese metal.
How would you account for the following:
Of the d4 species, Cr2+ is strongly reducing while manganese (III) is strongly oxidising.
Why do transition elements show variable oxidation states ? In 3d series (Sc to Zn), which elements shows the maximum number of oxidation state and why ?
Two metallic elements A and B have the following standard oxidation potentials: A = 0·40v B = - 0·80v. What would you expect if element A was added to an aqueous salt solution of element B? Give a reason for your answer.
Explain why Zn2+ salts are white whereas Cu2+ salts are coloured.
Electronic configuration of a transition element X in +3 oxidation state is [Ar]3d5. What is its atomic number?
The magnetic moment is associated with its spin angular momentum and orbital angular momentum. Spin only magnetic moment value of Cr3+ ion is ______.
Out of \[\ce{Cu2Cl2}\] and \[\ce{CuCl2}\], which is more stable and why?
When a brown compound of manganese (A) is treated with \[\ce{HCl}\] it gives a gas (B). The gas taken in excess, reacts with \[\ce{NH3}\] to give an explosive compound (C). Identify compounds A, B and C.
Although fluorine is more electronegative than oxygen, but the ability of oxygen to stabilise higher oxidation states exceeds that of fluorine. 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 catalysts given in Column I with the processes given in Column II.
| Column I (Catalyst) | Column II (Process) |
| (i) \[\ce{Ni}\] in the presence of hydrogen | (a) Zieglar Natta catalyst |
| (ii) \[\ce{Cu2C12}\] | (b) Contact process |
| (iii) \[\ce{V2O5}\] | (c) Vegetable oil to ghee |
| (iv) Finely divided iron | (d) Sandmeyer reaction |
| (v) \[\ce{TiCl4 + Al (CH3)3}\] | (e) Haber's Process |
| (f) Decomposition of KCIO3 |
Identify the metal and justify your answer.
\[\ce{MO3F}\]
On the basis of the figure given below, answer the following questions:
- Why Manganese has lower melting point than Chromium?
- Why do transition metals of 3d series have lower melting points as compared to 4d series?
- In the third transition series, identify and name the metal with the highest melting point.
Which of the following is non-metallic?
The complex showing a spin-span magnetic moment of 2.82 B.M. is :-
Which one among the following metals of the 3d series has the lowest melting point?
