Question

Identify the increasing order of effective magnetic moment of the following elements in their +2 oxidation state.

[Fe (Z = 26), Co (Z = 27), Ni (Z = 28), Cu (Z = 29)]

विकल्प

• Co < Cu < Fe < Ni

• Cu < Ni < Co < Fe

• Cu < Co < Fe < Ni

• Fe < Co < Ni < Cu

Answer 1

Cu < Ni < Co < Fe

Explanation:

\[\ce{Fe^{2+} -> 4s^0 3d^6}\]

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n = 4

µ = `sqrt("n"("n" + 2))`

µ = `sqrt(4(4 + 2))`

= 4.89

\[\ce{Co^{2+} -> 4s^0 3d^7}\]

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n = 3

µ = `sqrt(3(3 + 2))`

= 2.87

\[\ce{Ni^{2+} -> 4s^0 3d^8}\]

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n = 2

µ = `sqrt(2(2 + 2))`

= 2.82

\[\ce{Cu^{2+} -> 4s^0 3d^9}\]

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n = 1

µ = `sqrt(1(1 + 2))`

= 1.73

Increasing order of magnetic moment: Cu < Ni < Co < Fe