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प्रश्न
Calculate the number of unpaired electrons in the following gaseous ions:
Mn3+, Cr3+, V3+ and Ti3+. Which one of these is the most stable in an aqueous solution?
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उत्तर
| Gaseous ions | Electronic configurations | Number of unpaired electrons |
| Mn3+ | 3d4 4s0 | 4 |
| Cr3+ | 3d3 4s0 | 3 |
| V3+ | 3d2 4s0 | 2 |
| Ti3+ | 3d1 4s0 | 1 |
Of these, Cr3+ is most stable in aqueous solution because it has a half-filled \[\ce{t^3_2g}\] level.
संबंधित प्रश्न
What are interstitial compounds?
How would you account for the following: Transition metals form complex compounds.
Which of the d-block elements may not be regarded as the transition elements?
How would you account for the following:
Of the d4 species, Cr2+ is strongly reducing while manganese (III) is strongly oxidising.
Which among the following transition metal has the lowest melting point?
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.
Although Zirconium belongs to 4d transition series and Hafnium to 5d transition series even then they show similar physical and chemical properties because ______.
Although fluorine is more electronegative than oxygen, but the ability of oxygen to stabilise higher oxidation states exceeds that of fluorine. Why?
Assertion (A): Cu cannot liberate hydrogen from acids.
Reason (R): Because it has positive electrode potential.
Answer the following question:
Which element of the first transition series has highest third ionisation enthalpy?
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.
Transition metals can act as catalysts because these can change their oxidation state. How does \[\ce{Fe(III)}\] catalyse the reaction between iodide and persulphate ions?
Mention any three processes where transition metals act as catalysts.
On strong heating AgNO3, the gases evolved are:-
Which of the following characteristics of transition metals is associated with their catalytic activity?
Which property of transition metals enables them to behave as catalysts?
Explain the magnetic properties of d-block (or transition) elements.
Give a reason for the following.
Some transition metals and their compounds get attracted towards the magnetic field.
Match List-I with List-II.
| List-I | List-II |
| A. Haber process | I. Fe catalyst |
| B. Wacker oxidation | II. PdCl2 |
| C. Wilkinson catalyst | III. [(PPh3)3RhCl] |
| D. Ziegler catalyst | IV. TiCl4 with Al(CH3)3 |
Choose the correct answer from the options given below:
