Q32 / 200 · AP EAMCET 2001 · Chemistry

In the ground state, an element has 13 electrons in $\mathrm{M}$ shell. The element is

  • A
    copper
  • Correct answer
    B
    chromium
  • C
    nickel
  • D
    iron

Solution

$M$ 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 $\mathrm{Cr}$.

Hence, the correct answer is option: 'B'.

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