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कर्नाटक बोर्ड पी.यू.सी.पीयूसी विज्ञान 2nd PUC Class 12

Transition elements show magnetic moment due to spin and orbital motion of electrons. Which of the following metallic ions have almost same spin only magnetic moment? (i) CoX2+ (ii) CrX2+ (iii) MnX2

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प्रश्न

Transition elements show magnetic moment due to spin and orbital motion of electrons. Which of the following metallic ions have almost same spin only magnetic moment?

(i) \[\ce{Co^{2+}}\]

(ii) \[\ce{Cr^{2+}}\]

(iii) \[\ce{Mn^{2+}}\]

(iv) \[\ce{Cr^{3+}}\]

टीपा लिहा
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उत्तर

(i) \[\ce{Co^{2+}}\]

(iv) \[\ce{Cr^{3+}}\]

Explanation:

The magnetic moment of an electron/dipole moment is caused by its intrinsic properties of spin and electric charge. It depends upon the number of unpaired electrons in its valence shell. The more the number of unpaired electrons, the greater will be the value of the magnetic moment.

\[\ce{Co^{2+}}\] and \[\ce{Cr^{3+}}\] have same unpaired electrons i.e. 3 unpaired electrons. Hence they have the same spin only magnetic moment. 
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पाठ 8: The d-and f-Block Elements - Multiple Choice Questions (Type - I) [पृष्ठ १०९]

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एनसीईआरटी एक्झांप्लर Chemistry Exemplar [English] Class 12
पाठ 8 The d-and f-Block Elements
Multiple Choice Questions (Type - I) | Q 23 | पृष्ठ १०९

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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.

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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.

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