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प्रश्न
Transition elements show high melting points. Why?
Explain giving reasons:
Transition elements have higher melting and boiling points.
Why do transition elements have much higher melting points?
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उत्तर १
The high melting points of transition metals are attributed to the involvement of greater number of electrons in the interatomic metallic bonding from (n – 1) d-orbitals in addition to ns electrons.
उत्तर २
- Transition elements have higher melting and boiling points because their atoms are held together by strong metallic bonds.
- These metallic bonds have significant covalent character due to the presence of unpaired d-electrons that overlap between atoms.
- More unpaired d-electrons mean more covalent bonding and stronger metallic bonds, which require more energy to break.
- The close-packed structures of transition metals also contribute to the strong bonding and thus high melting and boiling points.
- Melting and boiling points generally increase up to the middle of the series because the number of unpaired d-electrons also increases up to that point.
संबंधित प्रश्न
Which of the following cations are coloured in aqueous solutions and why ?
Sc3+, V3+, Ti4+, Mn2+ (At. Nos. Sc = 21, V = 23, Ti = 22, Mn = 25)
The elements of 3d transition series are given as: Sc Ti V Cr Mn Fe Co
Answer the following: Write the element which shows maximum number of oxidation states. Give reason.
How would you account for the following: Transition metals form complex compounds.
Account for the following:
E° value for the Mn3+/Mn2+ couple is much more positive than that for Cr3+/Cr2+.
To what extent do the electronic configurations decide the stability of oxidation states in the first series of the transition elements? Illustrate your answer with examples.
Predict which of the following will be coloured in the aqueous solution?
Ti3+, V3+, Cu+, Sc3+, Mn2+, Fe3+ and Co2+. Give reasons for each.
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.
Give reasons:
E° value for the Mn3+/Mn2+ couple is much more positive than that for Fe3+/Fe2+.
Explain why transition metals and their compounds act as a catalyst.
Electronic configuration of Mn2+ 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 |
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?
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?
A complex in which dsp2 hybridisation takes place is ______.
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.
The number of terminal oxygen atoms present in the product B obtained from the following reactions is:
\[\ce{FeCr2O4 + Na2CO3 + O2 -> A + Fe2O3 + CO2}\]
\[\ce{A + H^+ -> B + H2O + Na^+}\]
Which one among the following metals of the 3d series has the lowest melting point?
Account for the following:
Copper has an exceptionally positive `"E"_("M"^(2+)//"M")^0` value.
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.)
