D-And F-Block Elements Ques 424
Question: Which of the following have maximum number of unpaired electrons
[BHU 2005]
Options:
A) $Fe^{3+}$
B) $Fe^{2+}$
C) $Co^{2+}$
D) $Co^{3+}$
Show Answer
Answer:
Correct Answer: A
Solution:
$Fe^{3+}$ $\rightarrow$ [Ar] $3d^6 4s^0$, number of unpaired electrons = 5
$Fe^{2+}$ $\rightarrow$ [Ar] $3d^6 4s^0$, number of unpaired electrons = 4
$Co^{2+}$ $\rightarrow$ [Ar] $3d^7 4s^0$, number of unpaired electrons = 3
$Co^{3+}$ $\rightarrow$ [Ar] $3d^6 4s^0,$ number of unpaired electrons = 4
