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

The magnetic moment is associated with its spin angular momentum and orbital angular momentum. Spin only magnetic moment value of Cr3+ ion is ______.

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प्रश्न

The magnetic moment is associated with its spin angular momentum and orbital angular momentum. Spin only magnetic moment value of Cr3+ ion is ______.

पर्याय

  • 2.87 B.M.

  • 3.87 B.M.

  • 3.47 B.M.

  • 3.57 B.M.

MCQ
रिकाम्या जागा भरा
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उत्तर

The magnetic moment is associated with its spin angular momentum and orbital angular momentum. Spin only magnetic moment value of Cr3+ ion is 3.87 B.M..

Explanation:

Cr3+ → [Ar]3d3 4s0, it has 3 unpaired electrons.

`mu = sqrt(n(n + 2))`

`mu = sqrt(3(3 + 2))`

`mu = sqrt(3(5))`

`mu = sqrt(15)`

μ = 3.87 B.M.

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पाठ 8: The d-and f-Block Elements - Multiple Choice Questions (Type - I) [पृष्ठ १०८]

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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 15 | पृष्ठ १०८

संबंधित प्रश्‍न

How would you account for the following? 

Transition metals exhibit variable oxidation states.

 


 
 
 

Complete the following chemical equations:

`(i) Cr_2O_7^(2-)+6Fe^(2+)+14H^+ ->`

`(ii) 2CrO_4^(2-)+2H^+ ->`

`(iii) 2MnO_4^-+5C_2O_4^(2-)+16H^+ ->`

 
 
 

Why +2 oxidation state of manganese is more stable?


The elements of 3d transition series are given as: Sc Ti V Cr Mn Fe Co

Answer the following: Write the element which shows maximum number of oxidation states. Give reason.


Which is a stronger reducing agent, Cr2+ or Fe2+ and why?


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?


Which one of the following ions is coloured?


Explain why Mn2+ is more stable than Fe2+ towards oxidation to +3 state. (At. no. of Mn = 25, Fe = 26)


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.


When acidified \[\ce{K2Cr2O7}\] solution is added to \[\ce{Sn^{2+}}\] salts then \[\ce{Sn^{2+}}\] changes to ______.


Transition elements form binary compounds with halogens. Which of the following elements will form \[\ce{MF3}\] type compounds?

(i) \[\ce{Cr}\]

(ii) \[\ce{Co}\]

(iii) \[\ce{Cu}\]

(iv) \[\ce{Ni}\]


Match the properties given in Column I with the metals given in Column II.

  Column I (Property) Column II (Metal)
(i)  An element which can show +8 oxidation state (a) \[\ce{Mn}\]
(ii)  3d block element that can show (b) \[\ce{Cr}\]
  upto +7 oxidation state (c) \[\ce{Os}\]
(iii)  3d block element with highest melting point (d) \[\ce{Fe}\]

When an oxide of manganese (A) is fused with KOH in the presence of an oxidising agent and dissolved in water, it gives a dark green solution of compound (B). Compound (B) disproportionates in neutral or acidic solution to give purple compound (C). An alkaline solution of compound (C) oxidises potassium iodide solution to a compound (D) and compound (A) is also formed. Identify compounds A to D and also explain the reactions involved.


Answer the following question:

Which element of the first transition series has lowest enthalpy of atomisation?


The standard electrode potentials of four elements A, B, C and D are – 3.05, – 1.66, – 0.40 and + 0.80. The highest chemical reactivity will be exhibited by


Among the following pairs of ions, the lower oxidation state in aqueous solution is more stable than the other in:-


Give reason for the following statement:

Physical and chemical properties of the 4d and 5d series of the transition elements are quite similar to expected.


Write the ionic equation for reaction of KI with acidified KMnO4.


For M2+/M and M3+/M2+systems, the EΘ values for some metals are as follows:

Cr2+/Cr −0.9 V
Mn2+/Mn −1.2 V
Fe2+/Fe −0.4 V
Cr3/Cr2+ −0.4 V
Mn3+/Mn2+ +1.5 V
Fe3+/Fe2+ +0.8 V

Use this data to comment upon:

The ease with which iron can be oxidised as compared to a similar process for either chromium or manganese metal.


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