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प्रश्न
Why do the transition elements have higher enthalpies of atomisation?
Explain giving reasons:
The enthalpies of atomisation of the transition metals are high.
How would you account for the following?
The transition elements exhibit high enthalpies of atomization.
How would you account for the following:
The transition elements have high enthalpies of atomization?
Give reasons for the following:
Transition elements have high enthalpies of atomization.
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उत्तर
- Transition elements have high enthalpies of atomization due to the presence of many unpaired electrons in their atoms.
- Unpaired electrons lead to strong interatomic interactions and stronger metallic bonding between atoms.
- The stronger the metallic bonds, the more energy is required to break these bonds, resulting in higher enthalpies of atomization.
- Elements of the second and third transition series have even higher enthalpies due to more frequent metal-metal bonding.
- This strong bonding also explains their high melting and boiling points.
APPEARS IN
संबंधित प्रश्न
Explain why is Fe3+ more stable than Fe2+?
ln which pair highest oxidation states of transition metals are found:
Account for the following:
Cu+ ion is unstable in aqueous solution.
In the series Sc (Z = 21) to Zn (Z = 30), the enthalpy of atomization of zinc is the lowest, i.e., 126 kJ mol−1. Why?
Explain briefly how +2 state becomes more and more stable in the first half of the first row transition elements with increasing atomic number?
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:
Electronic configurations
Transition metals with lowest melting point is ______.
Maximum magnetic moment is shown by ____________.
Read the passage given below and answer the following question:
The transition metals when exposed to oxygen at low and intermediate temperatures form thin, protective oxide films of up to some thousands of Angstroms in thickness. Transition metal oxides lie between the extremes of ionic and covalent binary compounds formed by elements from the left or right side of the periodic table. They range from metallic to semiconducting and deviate by both large and small degrees from stoichiometry. Since electron bonding levels are involved, the cations exist in various valence states and hence give rise to a large number of oxides. The crystal structures are often classified by considering a cubic or hexagonal close-packed lattice of one set of ions with the other set of ions filling the octahedral or tetrahedral interstices. The actual oxide structures, however, generally show departures from such regular arrays due in part to distortions caused by packing of ions of different size and to ligand field effects. These distortions depend not only on the number of d-electrons but also on the valence and the position of the transition metal in a period or group.
In the following questions, a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices on the basis of the above passage.
Assertion: Cations of transition elements occur in various valence states.
Reason: Large number of oxides of transition elements are possible.
Transition elements show high melting points. Why?
EΘ of Cu is + 0.34V while that of Zn is – 0.76V. Explain.
Answer the following question:
Which element of the first transition series has highest second ionisation enthalpy?
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 reasons for the following statement:
Transition metals and most of their compounds show paramagnetic behaviour.
The electrode potential of M2+/M of 3d-series elements shows the positive value for ______.
Account for the following:
Ce4+ is a strong oxidising agent.
A transition element X has an electronic configuration [Ar]4s23d3. Predict its likely oxidation states.
Write the ionic equation for reaction of KI with acidified KMnO4.
Explain the magnetic properties of d-block (or transition) elements.
