Atomic Structure - Result Question 70
####46. Which of the following statement (s) is (are) correct ? (1998, 2M)
(a) The electronic configuration of $Cr$ is $[Ar] 3 d^{5} 4 s^{1}$ (atomic number 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 number of $Ag=47$ )
(d) The oxidation state of nitrogen in $HN _3$ is -3
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Answer:
Correct Answer: 46. (b)
Solution:
- (a) $Cr=[Ar] 3 d^{5} 4 s^{1}$, an exception to aufbau principle.
(b) For a given value of $l, m$ can have any value from $(-l$ to $+l)$, so can have negative value.
(c) Ag is in copper group with $d^{10} s^{1}$ configuration, i.e. 46 electrons are spin paired.
