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प्रश्न
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:
Oxidation states
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उत्तर
The first series of transition metals (3d series) stable forms lower oxidation states like +2 and +3, and its highest states are strongly oxidizing. Conversely, down the respective vertical columns, the second (4d) and third (5d) series show an increasing stability in their higher oxidation states (such as +6 and +8), making their lower oxidation states relatively uncommon and unstable.
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संबंधित प्रश्न
What are interstitial compounds?
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)
Why do the transition elements have higher enthalpies of atomisation?
Account for the following:
E° value for the Mn3+/Mn2+ couple is much more positive than that for Cr3+/Cr2+.
Why is the highest oxidation state of a metal exhibited in its oxide or fluoride only?
How is the variability in oxidation states of transition metals different from that of the non-transition metals? Illustrate with examples.
What are alloys?
What can be inferred from the magnetic moment value of the following complex species?
| Example | Magnetic Moment (BM) |
| K2[MnCl4] | 5.9 |
NF3 is possible, but NF5 is not. Why?
Give reasons:
E° value for the Mn3+/Mn2+ couple is much more positive than that for Fe3+/Fe2+.
Explain why Mn2+ is more stable than Fe2+ towards oxidation to +3 state. (At. no. of Mn = 25, Fe = 26)
Interstitial compounds are formed when small atoms are trapped inside the crystal lattice of metals. Which of the following is not the characteristic property of interstitial compounds?
Explain why does colour of KMnO4 disappear when oxalic acid is added to its solution in acidic medium.
Answer the following question:
Which element of the first transition series has lowest enthalpy of atomisation?
Which of the following maxm magnetic moment?
A complex in which dsp2 hybridisation takes place is ______.
Account for the following:
Sc3+ is colourless whereas Ti3+ is coloured in an aqueous solution.
Which one among the following metals of the 3d series has the lowest melting point?
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.
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:
Atomic sizes
