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Question: Answered & Verified by Expert
In the ground state, an element has 13 electrons in $\mathrm{M}$ shell. The element is
ChemistryStructure of AtomAP EAMCETAP EAMCET 2001
Options:
  • A copper
  • B chromium
  • C nickel
  • D iron
Solution:
2803 Upvotes Verified Answer
The correct answer is: chromium
$M$ shell $=3$ rd shell
Electronic configuration
$=1 s^2, 2 s^2, 2 p^6, 3 s^2, 4 s^1, 3 d^5$
Number of $e^{-}$in 3rd shell $=3 s^2, 3 p^6, 3 d^5$
$=2+6+5=13$
Total $e^{-}=24$
So, the element is $\mathrm{Cr}$.

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