Among the following ions, which one has the highest paramagnetism?

Question

Among the following ions, which one has the highest paramagnetism? (A)

[C r (H_{2} O)_{6}]^{3 +}

(B)

{[Fe {(H_{2} O)}_{6}]}^{2 +}

(C)

[C u (H_{2} O)_{6}]^{2 +}

(D)

[Z n (H_{2} O)_{6}]^{2 +}

Tardigrade Admin · Accepted Answer

Water is a weak-field ligand, so the crystal field splitting paired in lower energy. Hence, electrons are not paired in lower energy d-orbitals (i.e., no pairing of electrons in d-orbitals occurs aganist the Hunds rule).

	Species	Oxidation state of central metal ion	Configuration of central metal ion	Number of unpaired d-electrons
A	$[C r (H_{2} O)_{6}]^{3 +}$	+3	$C r^{3 +} (3 d^{3})$	3
B	$[F e (H_{2} O)_{6}]^{2 +}$	+2	$F e^{2 +} (3 d^{6})$	4
C	$[C u (H_{2} O)_{6}]^{2 +}$	+2	$C u^{2 +} (3 d^{9})$	1
D	$[Z n (H_{2} O)_{6}]^{2 +}$	+2	$Z n^{2 +} (3 d^{10})$	0

The more the number of unpaired electrons, the higher is the paramagnetic character of the metal ion, As a result,

[F e (H_{2} O)_{6}]^{2 +}

has the highest paramagnetism.

Q. Among the following ions, which one has the highest paramagnetism?

[Cr(H2O)6]3+

Fe ( H 2 O) 6 2+

[Cu(H2O)6]2+

[Zn(H2O)6]2+

$[C r (H_{2} O)_{6}]^{3 +}$

${[Fe {(H_{2} O)}_{6}]}^{2 +}$

$[C u (H_{2} O)_{6}]^{2 +}$

$[Z n (H_{2} O)_{6}]^{2 +}$