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प्रश्न
Give reasons:
Transition metals show variable oxidation states.
Account for the following:
Transition metals show variable oxidation states.
Explain giving reasons:
Transition elements exhibit variable oxidation states.
Why do transition elements exhibit variable oxidation states?
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उत्तर १
- The variable oxidation states of transition elements are due to the participation of ns and (n − 1) d-electrons in bonding.
- A lower oxidation state is exhibited when the ns-electrons take part in bonding.
- Higher oxidation states are exhibited when the (n − 1) d-electrons take part in bonding.
- Since there is very little energy difference between these orbitals, both energy levels can be used for bond formation.
Thus, transition elements exhibit variable oxidation states.
उत्तर २
- In transition elements, the 3d and 4s electrons are close in energy and can be lost in different numbers during reactions.
- The involvement of both (n − 1) d and ns electrons in bonding allows multiple oxidation states.
- Stability of oxidation states is influenced by half-filled or fully filled d-subshells, leading to preferred oxidation numbers.
- For example, manganese shows oxidation states from +2 to +7, reflecting this variability.
Hence, transition elements show a wide range of oxidation states because they can lose different numbers of d and s electrons easily.
APPEARS IN
संबंधित प्रश्न
|
`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.
Why are Mn2+ compounds more stable than Fe2+ towards oxidation to their +3 state?
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: Crystal structure of oxides of transition metals often show defects.
Reason: Ligand field effect cause distortions in crystal structures.
The magnetic nature of elements depends on the presence of unpaired electrons. Identify the configuration of transition element, which shows highest magnetic moment.
Which of the following statements is not correct?
Explain why does colour of \[\ce{KMNO4}\] disappear when oxalic acid is added to its solution in acidic medium.
Give a reason for the following.
Some transition metals and their compounds get attracted towards the magnetic field.
Why are interstitial compounds well known for transition metals?
For M2+/M and M3+/M2+systems, the EΘ 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 ease with which iron can be oxidised as compared to a similar process for either chromium or manganese metal.
Decide which of the following atomic numbers are the atomic numbers of the inner transition elements:
29, 59, 74, 95, 102, 104
