Why Sc (Z = 21) is not considered as transition element ? from C

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 Multiple Choice QuestionsMultiple Choice Questions

271.

Assertion : La(OH)3 is more basic than Lu(OH)3

Reason : Size of Lu3+ increases and shows more covalent character.

  • If both assertion and reason are true and reason is the correct explanation of assertion.

  • If both assertion and reason are true but reason is not the correct explanation of assertion.

  • If assertion is true but reason is false.

  • If both assertion and reason are false


272.

Lanthanum the first element of lanthanide series has :

  • only unfilled 3d orbitals

  • unfilled 3d and 4d orbitals

  • unfilled 4d and 4forbitals

  • unfilled 4f and 5d orbitals


273.

Assertion : F- ion is a weak ligand and forms outer orbital complex.

Reason : F- ion cannot force the electrons of dz2 and dx2-y2 orbitals of the inner shell to occupy dxy, dyz and dzx orbitals of the same shell.

  • If both assertion and reason are true and reason is the correct explanation of assertion.

  • If both assertion and reason are true but reason is not the correct explanation of assertion.

  • If assertion is true but reason is false.

  • If both assertion and reason are false.


274.

Which of the following has more unpaired d-electrons ?

  • Zn

  • Fe2+

  • Ni3+

  • Cu+


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275.

How many structural isomers are possible for C4H9Cl ?

  • 2

  • 4

  • 8

  • 10


276.

What are constituents of 'Mischmetal'?

  • La, Fe

  • La, Ce

  • Fe, Ce

  • Ce, Cu


277.

Fungicides are organic compounds of :

  • mercury

  • fluorine

  • lead

  • chlorine


278.

In the periodic table actinides occupy :

  • III B group in 7th row

  • III B group in 6th row

  • III B group in 5th row

  • None of the above


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279.

Which of the following is diamagnetic ?

  • CuCl2

  • NiCl2

  • FeCl3

  • Cu2Cl2


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280.

Why Sc (Z = 21) is not considered as transition element ?

  • Properties of Sc are similar to alkali metals

  • 3d - orbitals are empty in its stable compound

  • Stable oxidation number of Sc is +2

  • Atomic volume of Sc is very large


B.

3d - orbitals are empty in its stable compound

Outer electronic configuration of Sc is 3d1 , 4s2

In the stable oxidation state ie , +3 , the electronic configuration of sc3+ is ;

Sc3+ : 1s2 , 2s2 2p6 , 3s2 3p6 3d0

It shows that 3d subshell is empty transition element can refer to those elements which form atleast one ion with a partially filled d shell of electrons .As Sc3+ has no electrons in its d orbital , hence , it is not considered as transition element in the stricter sense .


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