# Which of the following statement is (are) correct ?

$\begin{array}{1 1}(a)\;The\; electronic \;configuration\; of\; Cr\; is\; [Ar]3d^5,4s^1(Atomic\;no\;of\;Cr=24)\\(b)\;The\;magnetic\;quantum\; number\;may\;have\;a\;negative\;value\\(c)\;In \;silver \;atom,23\;electrons\;have\;a\;spin\;of\;one\;type\;and\;24\;of\;the\;opposite\;type\;(Atomic\;no\;of\;Ag=47)\\(d)\;All\;of\;these\end{array}$

$_{24}Cr:1s^2,2s^22p^6,3s^23p^63d^5,4s^1$
(d-acquires half-filled nature)
For $d=1$ m can have -1,0,+1 values
In Silver
$_{47}Ag$ :$1s^2,2s^22p^6,3s^23p^63d^{10},4s^24p^64d^{10}5s^1$
Hence (d) is the correct answer.
edited Jan 13, 2014