D-And F-Block Elements Ques 417

Question: Electronic configuration of $ Cu(Z=29) $ is

[Pb. CET 2001]

Options:

A) $ [Ar]3d^{9}4s^{2} $

B) $ [Ar]3d^{10}4s^{1} $

C) $ [Ar]3d^{5}4s^{2} $

D) $ [Ar]3d^{6}4s^{2} $

Show Answer

Answer:

Correct Answer: B

Solution:

The expected electronic configuration of Cu (29) is $ [Ar]\ 3d^{9}4s^{2} $ but actually it is found to be $ [Ar]\ 3d^{10}4s^{1} $ .

This is because fully filled d orbitals are more stable than incompletely filled d-orbitals.

So there is a migration of one $ {{e}^{-}} $ , from 4s orbital to 3d orbital to give a more stable configuration.



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