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प्रश्न
Why do transition metal ions possess a great tendency to form complexes?
उत्तर
Due to the small size of transition metal atoms or their cations and high effective nuclear charge, they have a high positive charge density on them. This high positive charge density makes the atoms or cations to attract the lone pairs of e– from the ligands.
The transition metal cation or atoms have vacant d-orbital in which they can accommodate the lone pairs of e– donated by ligands and thus can form L → M coordinate bonds.
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संबंधित प्रश्न
Two metallic elements A and B have the following standard oxidation potentials: A = 0·40v B = - 0·80v. What would you expect if element A was added to an aqueous salt solution of element B? Give a reason for your answer.
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.
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\[\ce{Fe^{3+}_{ (aq)} + e^- -> Fe^{2+}_{ (aq)}}\], E0 = +0.77 V
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What is the cell potential for the redox reaction?
A transition element X has an electronic configuration [Ar]4s23d3. Predict its likely oxidation states.
The second ionization enthalpies of chromium and manganese are 1592 and 1509 kJ/mol respectively. Explain the lower value of Mn.
What is the oxidation state of chromium in chromate ion and dichromate ion?
Why are interstitial compounds well known for transition metals?
