Consider the aqueous high-spin M^2+ ions of the 3d series from Ti^2+ to Zn^2+ (nine ions). The number of these ions whose spin-only magnetic moment exceeds 4 BM is:

JEE Advanced levelSingle correct optionDifficulty 3 of 3df147

Consider the aqueous high-spin $M X^{2 +}$ ions of the 3d series from $Ti X^{2 +}$ to $Zn X^{2 +}$ (nine ions). The number of these ions whose spin-only magnetic moment exceeds 4 BM is:

Unpaired electrons are

Ti X^{2 +}

V X^{2 +}

Cr X^{2 +}

Mn X^{2 +}

Fe X^{2 +}

Co X^{2 +}

Ni X^{2 +}

Cu X^{2 +}

Zn X^{2 +}

0. Moments above 4 BM need

n \geq 4

(4.90, 5.92, 4.90), so only

Cr X^{2 +}

Mn X^{2 +}

and

Fe X^{2 +}

qualify: 3.