The correct electronic configuration of Cr is____________________?
Correct answer: D. [Ar]4s13d5
- A. [Ar]4s23d4
- B. [Ar] 4s23d4
- C. [Ar]4s03d5
- D. [Ar]4s13d5
Explanation
Chromium has the configuration [Ar]4s1 3d5 rather than [Ar]4s2 3d4 because a half-filled 3d5 subshell has extra stability. One 4s electron is promoted into the 3d subshell. The likely mistake is choosing a or b, which are the same configuration and apply the usual filling order without considering the stability of a half-filled d subshell.
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About Electronic Structure of d-Block Elements
The electronic structure of d-block elements covers the filling of the (n-1)d and ns orbitals, general electronic configurations, and the exceptions shown by chromium and copper. It explains how partially filled d orbitals produce variable oxidation states, coloured ions, magnetic behaviour and complex formation, while distinguishing transition elements from elements with completely filled d subshells.
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