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प्रश्न
Comment on the statement that elements of the first transition series possess many properties different from those of heavier transition elements.
उत्तर
- In the first transition series, lower oxidation states are more stable, while heavier transition elements have higher oxidation states.
- The 5d transition series exhibits higher ionization enthalpy compared to the 3d and 4d transition series.
- M-M bonding is prevalent in heavier transition metals, but less so in the first series.
- The elements in the first transition series do not form complexes with coordination numbers of 7 or 8.
- Elements in the first series can form high or low-spin complexes based on ligand strength, while those in the other series form low-spin complexes regardless of ligand strength.
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संबंधित प्रश्न
What are the transition elements? Write two characteristics of the transition elements.
|
`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.
Calculate the ‘spin only’ magnetic moment of \[\ce{M^{2+}_{ (aq)}}\] ion (Z = 27).
Write the formula of an oxo-anion of Chromium (Cr) in which it shows the oxidation state equal to its group number
How would you account for the following?
Transition metals and their compounds act as catalysts.
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.
Which among the following transition metal has the lowest melting point?
In lake test for Al3+ ions, there is the formation of coloured ‘floating lake’. It is due to ______.
The magnetic nature of elements depends on the presence of unpaired electrons. Identify the configuration of transition element, which shows highest magnetic moment.
Why is \[\ce{HCl}\] not used to make the medium acidic in oxidation reactions of \[\ce{KMnO4}\] in acidic medium?
Which of the following will not act as oxidising agents?
(i) \[\ce{CrO3}\]
(ii) \[\ce{MoO3}\]
(iii) \[\ce{WO3}\]
(iv) \[\ce{CrO^{2-}4}\]
Why EΘ values for Mn, Ni and Zn are more negative than expected?
A solution of \[\ce{KMnO4}\] on reduction yields either a colourless solution or a brown precipitate or a green solution depending on pH of the solution. What different stages of the reduction do these represent and how are they carried out?
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 lowest enthalpy of atomisation?
Mention the type of compounds formed when small atoms like H, C and N get trapped inside the crystal lattice of transition metals. Also give physical and chemical characteristics of these compounds.
Which of the following is non-metallic?
If enthalpies of formation of C2H4(g), CO2(g) and H2O(l) at 25°C and 1 atm pressure are 52, – 394 and – 286 kJ/mol respectively, the change in ethalpy for combustion of C2H4 is equal to
Account for the following:
Transition metals form alloys.
The disproportionation of \[\ce{MnO^{2-}_4}\] in acidic medium resulted in the formation of two manganese compounds A and B. If the oxidation state of Mn in B is smaller than that of A, then the spin-only magnetic moment (µ) value of B in BM is ______. (Nearest integer)
