MCQ
The electronic configuration of the element of atomic number $ 27 $ is
  • A
    $1{s^2},\;2{s^2}2{p^6},\;3{s^2}3{p^6},\;4s\;( \uparrow \downarrow )\;4p\;( \uparrow \downarrow )( \uparrow \downarrow )( \uparrow \downarrow )\;5s\;( \uparrow )$
  • B
    $1{s^2},\;2{s^2}2{p^6},\;3{s^2}3{p^6}3d\;( \uparrow \downarrow )( \uparrow \downarrow )( \uparrow \downarrow ),\;4s\;( \uparrow \downarrow )\;4p\;( \uparrow )$
  • C
    $1{s^2},\;2{s^2}2{p^6},\;3{s^2}3{p^6},\;3d\;( \uparrow \downarrow )( \uparrow \downarrow )( \uparrow \downarrow )( \uparrow \downarrow ),\;4s\;( \uparrow )$
  • $1{s^2},\;2{s^2}2{p^6},\;3{s^2}3{p^6},\;3d\;( \uparrow \downarrow )( \uparrow \downarrow )( \uparrow )( \uparrow )( \uparrow )\;4s\;( \uparrow \downarrow )$

Answer

Correct option: D.
$1{s^2},\;2{s^2}2{p^6},\;3{s^2}3{p^6},\;3d\;( \uparrow \downarrow )( \uparrow \downarrow )( \uparrow )( \uparrow )( \uparrow )\;4s\;( \uparrow \downarrow )$
d
(d) According to Aufbau’s rule.

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