JEE Main 2023 — Chemistry Physical Chemistry

2023mcqeasy

The radius of the 2 $^{nd}$ orbit of ${\mathrm{Li}}^{2+}$ is $x$ . The expected radius of the 3 $^{rd}$ orbit of ${\mathrm{Be}}^{3+}$ is

Official previous-year question

Held on 25 Jan 2023 · Verified 6 Jul 2026.

Options

A
$\frac{9}{4}x$
B
$\frac{4}{9}x$
C
$\frac{27}{16}x$
D
$\frac{16}{27}x$

Did you get this right?

Solution

Radius of orbit $(r)=0.529\times \frac{{n}^{2}}{Z}$

Where, n = principal quantum number of orbit

Z = Atomic number

$({r}_{{\mathrm{Li}}^{2+}}{)}_{n=2}=0.529\times \frac{(2{)}^{2}}{3}=x-----(1)$

${({r}_{{\mathrm{Be}}^{3+}})}_{n=3}=0.529\times \frac{(3{)}^{2}}{4}-----(2)$

Divide equation (1) by equation (2)

$\frac{{({r}_{{\mathrm{Li}}^{2+}})}_{n=2}}{{({r}_{{\mathrm{Be}}^{3+}})}_{n=3}}=\frac{0.529\times \frac{(2{)}^{2}}{3}}{0.529\times \frac{(3{)}^{2}}{4}}$

$\Rightarrow \frac{x}{({r}_{{\mathrm{Be}}^{3+}}{)}_{n=3}}=\frac{16}{27}$

$\therefore {({r}_{{\mathrm{Be}}^{3+}})}_{n=3}=\frac{27x}{16}$

Your note

JEE Main Physical Chemistry in other years

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JEE Main 2023 — Chemistry Physical Chemistry

2023mcqeasy

The radius of the 2 $^{nd}$ orbit of ${\mathrm{Li}}^{2+}$ is $x$ . The expected radius of the 3 $^{rd}$ orbit of ${\mathrm{Be}}^{3+}$ is

Official previous-year question

Held on 25 Jan 2023 · Verified 6 Jul 2026.

Options

A
$\frac{9}{4}x$
B
$\frac{4}{9}x$
C
$\frac{27}{16}x$
D
$\frac{16}{27}x$

Did you get this right?

Solution

Radius of orbit $(r)=0.529\times \frac{{n}^{2}}{Z}$

Where, n = principal quantum number of orbit

Z = Atomic number

$({r}_{{\mathrm{Li}}^{2+}}{)}_{n=2}=0.529\times \frac{(2{)}^{2}}{3}=x-----(1)$

${({r}_{{\mathrm{Be}}^{3+}})}_{n=3}=0.529\times \frac{(3{)}^{2}}{4}-----(2)$

Divide equation (1) by equation (2)

$\frac{{({r}_{{\mathrm{Li}}^{2+}})}_{n=2}}{{({r}_{{\mathrm{Be}}^{3+}})}_{n=3}}=\frac{0.529\times \frac{(2{)}^{2}}{3}}{0.529\times \frac{(3{)}^{2}}{4}}$

$\Rightarrow \frac{x}{({r}_{{\mathrm{Be}}^{3+}}{)}_{n=3}}=\frac{16}{27}$

$\therefore {({r}_{{\mathrm{Be}}^{3+}})}_{n=3}=\frac{27x}{16}$

Your note

JEE Main Physical Chemistry in other years

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Work through every JEE Main Physical Chemistry PYQ, year by year.

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JEE Main 2023 — Chemistry Physical Chemistry

Options

Did you get this right?

Solution

Your note

JEE Main Physical Chemistry in other years

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JEE Main 2023 — Chemistry Physical Chemistry

Options

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