Multiple Choice Questions

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The spin only magnetic moment of Mn4+ ion is nearly

  • 3BM

  • 6BM

  • 4BM

  • 5BM


C.

4BM

The electronic configuration of Mn is

25Mn = [Ar] 3d5 4s2

Mn4+ = [Ar] 3d3

Thus, three unpaired electrons are present.

Spin only magnetic moment, µ=√n(n+2)

                  n = 3

                  µ =√3(3+2)

                  µ =√15 = 3.87

                  µ = 4 BM


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In a transition series, with increase in atomic-number, the paramagnetism

  • increases gradually

  • decreases gradually

  • first increases to a maximum and then decreases

  • first decreases to a minimum and then increases


In chromite ore, the oxidation number of iron and chromium are respectively

  • +3, +2

  • +3, +6

  • +2, +6

  • +2, +3


The electronic configuration of Cu2+ ion is

  • [Ar] 3d8 4s1

  • [Ar] 3d9 4s0

  • [Ar] 3d7 4s2

  • [Ar] 3d8 4s0


Which one of the following shows highest magnetic moment?

  • Fe2+

  • Co2+

  • Cr3+

  • Ni2+


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An element with atomic number 21 is a

  • halogen

  • representative element

  • transition element

  • alkali metal


Which of the following has the maximum number of unpaired 'd' electrons?

  • Zn2+

  • Fe2+

  • Ni3+

  • Cu+


Which of the following is a negatively charged bidentate ligand?

  • Cyano

  • Ethylene diamine

  • Acetato

  • Dimethyl glyoximato


In chromite ore, the oxidation number of iron, and chromium are respectively

  • +3,+2

  • +3,+6

  • +2,+6

  • +2,+3


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Mercury is a liquid metal because

  • it has a completely filled s orbital

  • it has a small atomic size

  • it has a completely filled d orbital that prevents d-d overlapping of orbitals

  • it has a completely filled d orbital that causes d-d overlapping


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