question_answer

The number of elements in the transition metal series Sc through Zn that have four unpaired electrons in their + 2 state are

A)  2                      

B)  4

C)  5                      

D)  6

Correct Answer: A

Solution :

\[F{{e}^{2+}}\,\,(z=26)=Ar\,\,3{{d}^{6}}\] \[C{{r}^{2+}}\,\,(z=24)=Ar\,\,3{{d}^{4}}\]