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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.
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संबंधित प्रश्न
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.
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.
Give reasons:
E° value for the Mn3+/Mn2+ couple is much more positive than that for Fe3+/Fe2+.
Explain why Zn2+ salts are white whereas Cu2+ salts are coloured.
In lake test for Al3+ ions, there is the formation of coloured ‘floating lake’. It is due to ______.
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.
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 fluorine is more electronegative than oxygen, but the ability of oxygen to stabilise higher oxidation states exceeds that of fluorine. Why?
Assertion: Separation of \[\ce{Zr}\] and \[\ce{Hf}\] is difficult.
Reason: Because \[\ce{Zr}\] and \[\ce{Hf}\] lie in the same group of the periodic table.
Identify A to E and also explain the reactions involved.
Fill in the blanks by choosing the appropriate word(s) from those given in the brackets:
(activation energy, Threshold energy, increased, lowered, partially, full, d-d transition, Benzoic acid, benzaldehyde)
Only those transition metal ions will be coloured which have ______ filled d-orbitals facilitating ______.
Which of the following statements is not correct?
Why are all copper halides known except that copper iodide?
Give reasons for the following statement:
Transition metals and most of their compounds show paramagnetic behaviour.
Consider the following standard electrode potentials (E° in volts) in aqueous solution:
| Element | M3+/M | M+/M |
| Al | - 1.66 | +0.55 |
| Tl | + 1.26 | -0.34 |
Based on these data, which of the following statements is correct?
A transition element X has an electronic configuration [Ar]4s23d3. Predict its likely oxidation states.
Account for the following:
Eu2+ with electronic configuration [Xe]4f76s2 is a strong reducing agent.
Account for the following:
Zirconium (Zr) and Hafnium (Hf) are difficult to separate.
Describe the oxidising action of potassium dichromate and write the ionic equation for its reaction with H2S.
The E° value for the Mn2+/Mn2+ couple is more positive than that of Cr3+/Cr2+ or Fe3+/Fe2+ due to the change of:
