Atomic Structure - Result Question 58
####34. The correct ground state electronic configuration of chromium atom is
(a) $[Ar] 3 d^{5} 4 s^{1}$
(b) $[Ar] 3 d^{4} 4 s^{2}$
(c) $[Ar] 3 d^{6} 4 s^{0}$
(d) $[Ar] 4 d^{5} 4 s^{1}$
$(1989,1 M)$
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Answer:
Correct Answer: 34. (a)
Solution:
- $\operatorname{Cr}(24)=\underbrace{1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6}} _{\operatorname{Ar}} 3 d^{5} 4 s^{1}$
The above configuration is exception to Aufbau’s principle.
