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प्रश्न
How would you account for the following: Transition metals form complex compounds.
Account for the following:
Transition metals form a large number of complexes.
Account for the following:
Transition metals form large number of complex compounds.
Give reasons for the following:
Transition elements form complex compounds.
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उत्तर १
The transition elements form complexes because they are able to accept pairs of electrons from donor molecules or ions to form dative covalent bonds. This happens because they have vacant orbitals of suitable energy which can accept the non-bonding pairs from the ligands.
उत्तर २
The transition elements form complexes because of the following reasons:
- Comparatively smaller size of their metal ions.
- Their high ionic charges.
- Availability of vacant d-orbitals so that these orbitals can accept lone pairs of electrons donated by the ligands.
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संबंधित प्रश्न
In 3d series (Sc to Zn), which element has the lowest enthalpy of atomisation and why?
How would you account for the following?
Zr (Z = 40) and Hf (Z = 72) have almost identical radii.
Which is the most stable oxidation state of iron?
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: Transition metals form protective oxide films.
Reason: Oxides of transition metals are always stoichiometric.
Assertion: The highest oxidation state of osmium is +8.
Reason: Osmium is a 5d-block element.
A violet compound of manganese (A) decomposes on heating to liberate oxygen and compounds (B) and (C) of manganese are formed. Compound (C) reacts with KOH in the presence of potassium nitrate to give compound (B). On heating compound (C) with conc. \[\ce{H2SO4}\] and \[\ce{NaCl}\], chlorine gas is liberated and a compound (D) of manganese along with other products is formed. Identify compounds A to D and also explain the reactions involved.
Which of the following ions has the electronic configuration 3d6?
(Atomic number: Mn = 25, Co = 27, Ni = 28)
Account for the following:
Eu2+ with electronic configuration [Xe]4f76s2 is a strong reducing agent.
Explain the use of different transition metals as catalysts.
Give a reason for the following:
Zinc, cadmium and mercury are considered as d-block elements but not regarded as transition elements.
