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प्रश्न
Why do the transition elements have higher enthalpies of atomisation?
Explain giving reason:
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 explains their high melting and boiling points as well.
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संबंधित प्रश्न
Account for the following:
Mn shows the highest oxidation state of +7 with oxygen but with fluorine, it shows oxidation state of +4.
How would you account for the following : Transition metals form coloured compounds
|
`E_((M^(2+)/M)` |
Cr | Mn | Fe | Co | Ni | Cu |
| -0.91 | -1.18 | -0.44 | -0.28 | -0.25 | -0.34 |
From the given data of E0 values, answer the following questions :
(1) Why is `E_(((Cu^(2+))/(Cu)))` value exceptionally positive
(2) Why is `E_(((Mn^(2+))/(Mn)))` value is highly negative as compared to other elements
(3) Which is the stronger reducing agents Cr2+ or Fe2+ ? Give Reason.
Out of Mn3+ and Cr3+, which is more paramagnetic and why ?
(Atomic nos. : Mn = 25, Cr = 24)
What is meant by ‘disproportionation’?
Write balanced chemical equations for the conversion of `CrO_4^(2-)` to `Cr_2O_7^(2-)` in acidic medium and `Cr_2O_7^(2-)` to `CrO_4^(2-)`
in basic medium.
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.
Which of the following ions show higher spin only magnetic moment value?
(i) \[\ce{Ti^3+}\]
(ii) \[\ce{Mn2+}\]
(iii) \[\ce{Fe2+}\]
(iv) \[\ce{Co3+}\]
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 |
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.
It has been observed that first ionization energy of 5 d series of transition elements are higher than that of 3d and 4d series, explain why?
Which of the following maxm magnetic moment?
Which one of the following characters tie of the transition metal is associated with higher catalytic activity?
Why are all copper halides known except that copper iodide?
Account for the following:
Sc3+ is colourless whereas Ti3+ is coloured in an aqueous solution.
Which of the following transition metals shows +1 and +2 oxidation states?
Consider the following standard electrode potential values:
\[\ce{Fe^{3+}_{ (aq)} + e^- -> Fe^{2+}_{ (aq)}}\], E0 = +0.77 V
\[\ce{MnO^{-4}_{ (aq)} + 8H^+ + 5e^- -> Mn^{2+}_{ (aq)} + 4H2O_{(l)}}\], E0 = +1.51 V
What is the cell potential for the redox reaction?
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.
