JEE Main 2024 — Chemistry Physical Chemistry

2024integerhard

Total number of ions from the following with noble gas configuration is

${\mathrm{Sr}}^{2+}(Z=38),{\mathrm{Cs}}^{+}(Z=55),{\mathrm{La}}^{2+}(Z=57){\mathrm{Pb}}^{2+}$ $(Z=82),{\mathrm{Yb}}^{2+}(Z=70)\text{ and }{\mathrm{Fe}}^{2+}(Z=26)$

Official previous-year question

Held on 27 Jan 2024 · Verified 6 Jul 2026.

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Solution

Noble gas configuration $={\mathrm{ns}}^{2}{\mathrm{np}}^{6}$

$[{}_{38}{\mathrm{Sr}}^{2+}]={[}_{36}\mathrm{Kr}]$

$[{\mathrm{Cs}}^{+}]={[}_{54}\mathrm{Xe}]$

$[{{\mathrm{Yb}}_{70}}^{2+}]={[}_{54}\mathrm{Xe}]4{f}^{14}$

$[{}_{57}{\mathrm{La}}^{2+}]={[}_{54}\mathrm{Xe}]5{d}^{1}$

$[{}_{82}{\mathrm{Pb}}^{2+}]={[}_{54}\mathrm{Xe}]4{f}^{14}5{d}^{10}6{s}^{2}$

$[{}_{26}{\mathrm{Fe}}^{2+}]={[}_{18}\mathrm{Ar}]3{d}^{6}$

${\mathrm{Cs}}^{+}$ and ${\mathrm{Sr}}^{2+}$ have noble gas configuration, which are $\mathrm{Xe}$ and $\mathrm{Kr}$ , respectively.

Hence, the answer is $2$ .

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JEE Main 2024 — Chemistry Physical Chemistry

2024integerhard

Total number of ions from the following with noble gas configuration is

${\mathrm{Sr}}^{2+}(Z=38),{\mathrm{Cs}}^{+}(Z=55),{\mathrm{La}}^{2+}(Z=57){\mathrm{Pb}}^{2+}$ $(Z=82),{\mathrm{Yb}}^{2+}(Z=70)\text{ and }{\mathrm{Fe}}^{2+}(Z=26)$

Official previous-year question

Held on 27 Jan 2024 · Verified 6 Jul 2026.

Did you get this right?

Solution

Noble gas configuration $={\mathrm{ns}}^{2}{\mathrm{np}}^{6}$

$[{}_{38}{\mathrm{Sr}}^{2+}]={[}_{36}\mathrm{Kr}]$

$[{\mathrm{Cs}}^{+}]={[}_{54}\mathrm{Xe}]$

$[{{\mathrm{Yb}}_{70}}^{2+}]={[}_{54}\mathrm{Xe}]4{f}^{14}$

$[{}_{57}{\mathrm{La}}^{2+}]={[}_{54}\mathrm{Xe}]5{d}^{1}$

$[{}_{82}{\mathrm{Pb}}^{2+}]={[}_{54}\mathrm{Xe}]4{f}^{14}5{d}^{10}6{s}^{2}$

$[{}_{26}{\mathrm{Fe}}^{2+}]={[}_{18}\mathrm{Ar}]3{d}^{6}$

${\mathrm{Cs}}^{+}$ and ${\mathrm{Sr}}^{2+}$ have noble gas configuration, which are $\mathrm{Xe}$ and $\mathrm{Kr}$ , respectively.

Hence, the answer is $2$ .

Your note

JEE Main Physical Chemistry in other years

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JEE Main 2024 — Chemistry Physical Chemistry

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Solution

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JEE Main Physical Chemistry in other years

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Organic Chemistry

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JEE Main 2024 — Chemistry Physical Chemistry

Did you get this right?

Solution

Your note

JEE Main Physical Chemistry in other years

More JEE Main Physical Chemistry questions

Other Chemistry topics for JEE Main

Organic Chemistry

Inorganic Chemistry

Keep practicing Physical Chemistry