Question

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

• A. The electronic configuration of Cr is [Ar] $3d^5 \, 4 s^1$ (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

Answer 1

Answer: (C)

In silver atom, 23 electrons have a spin of one type and 24 of the opposite type, (atomic number of Ag = 47)

Answer 2

(a) Cr = [Ar] $3d^5 \, 4s^1$, 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.