question_answer

Which of the following is paramagnetic [Pb. CET 2000]

A) \[N{{i}^{++}}\]

B) \[C{{u}^{+}}\]

C) \[Z{{n}^{++}}\]

D) \[S{{c}^{+++}}\]

Correct Answer: A

Solution :

Elements or ions containing unpaired electrons are paramagnetic. \[_{28}Ni=[Ar]\ 3{{d}^{8}}4s_{2}^{{}}\] ;  \[N{{i}^{2+}}=[Ar]\ 3{{d}^{8}}4{{s}^{0}}\]  \[N{{i}^{2+}}\]Stage            Because \[N{{i}^{2+}}\] have 2 unpaired electrons in 3d subshell therefore it is paramagnetic.