Which of the following has maximum number of unpaired d-electrons?

Question

Which of the following has maximum number of unpaired d-electrons? (A) Fe 2+ (B) Cu + (C) Zn (D) Ni 3+

Tardigrade Admin · Accepted Answer

Fe 2+=[ Ar ] 3 d6 4 s0 ⇒ 4 unpaired electrons. Cu +=[ Ar ] 3 d10 4 s0 ⇒ No unpaired electron Zn =[ Ar ] 3 d10 4 s2 ⇒ No unpaired electron Ni 3+=[ Ar ] 3 d7 4 s0 ⇒ 3-unpaired electrons

Q. Which of the following has maximum number of unpaired $d$ -electrons?

$F e^{2 +}$

$C u^{+}$

$Z n$

$N i^{3 +}$

$F e^{2 +} = [A r] 3 d^{6} 4 s^{0}$
$\Rightarrow 4$ unpaired electrons.
$C u^{+} = [A r] 3 d^{10} 4 s^{0}$
$\Rightarrow$ No unpaired electron
$Z n = [A r] 3 d^{10} 4 s^{2}$
$\Rightarrow$ No unpaired electron
$N i^{3 +} = [A r] 3 d^{7} 4 s^{0}$
$\Rightarrow 3$ -unpaired electrons

Q. Which of the following has maximum number of unpaired d-electrons?

Fe2+

Cu+

Zn

Ni3+