Number of paramagnetic ions among the following d- and f-block metal ions is \_\_\_\_ . \(\mathrm{Mn}^{2+}, \mathrm{Cu}^{2+}, \mathrm{Zn}^{2+}, \mathrm{Yb}^{2+}, \mathrm{Sc}^{3+}, \mathrm{La}^{3+}, \mathrm{Gd}^{3+}, \mathrm{Lu}^{3+}, \mathrm{Ti}^{4+}\), \(\mathrm{Ce}^{4+}\) (Atomic number of \(\mathrm{Mn}=25, \mathrm{Cu}=29, \mathrm{Zn}=30\), \(\mathrm{Yb}=70, \mathrm{Sc}=21, \mathrm{La}=57, \mathrm{Gd}=64, \mathrm{Lu}=71\), \(\mathrm{Ti}=22, \mathrm{Ce}=58\) )

JEE Main · 2026 · 02 Apr 2026 · Shift 2 · d and f Block Elements

Number of paramagnetic ions among the following d- and f-block metal ions is ____ .

Mn^{2 +}, Cu^{2 +}, Zn^{2 +}, Yb^{2 +}, Sc^{3 +}, La^{3 +}, Gd^{3 +}, Lu^{3 +}, Ti^{4 +}

Ce^{4 +}

(Atomic number of

Mn = 25, Cu = 29, Zn = 30

Yb = 70, Sc = 21, La = 57, Gd = 64, Lu = 71

Ti = 22, Ce = 58

)

Answer: 3

An ion is paramagnetic when it carries unpaired electrons.

Mn X^{2 +}

(

3 d^{5}

) has five,

Cu X^{2 +}

(

3 d^{9}

) has one, and

Gd X^{3 +}

(

4 f^{7}

) has seven, so these three are paramagnetic. The rest are diamagnetic:

Zn X^{2 +}

(

3 d^{10}

Yb X^{2 +}

(

4 f^{14}

) and

Lu X^{3 +}

(

4 f^{14}

) have filled shells, while

Sc X^{3 +}

La X^{3 +}

Ti X^{4 +}

and

Ce X^{4 +}

have empty

d

f

shells. The number of paramagnetic ions is

3

JEE Main · 2026 · 02 Apr 2026 · Shift 2 · Integer answer