Which one of the following statements is… - NEET UG 2017 Chemistry PYQ

NEET UG 2017 — Chemistry Physical Chemistry

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Which one of the following statements is wrong?

Official previous-year question

Held on 30 Apr 2017 · Verified 9 Jul 2026.

Options

A
de-Broglie's wavelength is given by $\lambda =\frac{h}{\mathrm{mv}}$ , were $m=$ mass of the particle, $v=$ group velocity of the particle.
B
The uncertainty principle is $\Delta E\times \Delta t\geq \frac{h}{4\pi }$ .
C
Half-filled and fully-filled orbitals have greater stability due to the greater exchange energy, greater symmetry and more balanced arrangement.
D
The energy of $2s$ orbital is less than the energy of $2p$ orbital in case of hydrogen-like atoms.

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Solution

(i) $\lambda =\frac{h}{p}=\frac{h}{\mathrm{mv}}$

(ii) $\Delta x.\Delta p=\frac{h}{4\pi }$

$\Delta x\times \frac{\Delta p\times \mathrm{dt}}{\Delta t}\geq \frac{h}{4\pi }$ $\therefore \frac{\Delta p}{\Delta t}=f$

$f\Delta x \Delta t\geq \frac{h}{4\pi }$ , $f\Delta x=\Delta E$

$\Delta E.\Delta t\geq \frac{h}{4\pi }$

(iii) ${3}^{\mathrm{rd}}$ statement is true.

(iv) The energy of $2s-$ orbital and $2p-$ orbital in case of hydrogen like atoms is equal because they are single electron species.

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Options

de-Broglie's wavelength is given by $\lambda =\frac{h}{\mathrm{mv}}$ , were $m=$ mass of the particle, $v=$ group velocity of the particle.

The uncertainty principle is $\Delta E\times \Delta t\geq \frac{h}{4\pi }$ .

Half-filled and fully-filled orbitals have greater stability due to the greater exchange energy, greater symmetry and more balanced arrangement.

The energy of $2s$ orbital is less than the energy of $2p$ orbital in case of hydrogen-like atoms.

Solution

(i) $\lambda =\frac{h}{p}=\frac{h}{\mathrm{mv}}$

(ii) $\Delta x.\Delta p=\frac{h}{4\pi }$

$\Delta x\times \frac{\Delta p\times \mathrm{dt}}{\Delta t}\geq \frac{h}{4\pi }$ $\therefore \frac{\Delta p}{\Delta t}=f$

$f\Delta x \Delta t\geq \frac{h}{4\pi }$ , $f\Delta x=\Delta E$

$\Delta E.\Delta t\geq \frac{h}{4\pi }$

(iii) ${3}^{\mathrm{rd}}$ statement is true.

(iv) The energy of $2s-$ orbital and $2p-$ orbital in case of hydrogen like atoms is equal because they are single electron species.

Options

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Solution

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Options

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Solution

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NEET UG Physical Chemistry in other years

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Other Chemistry topics for NEET UG

Organic Chemistry

Inorganic Chemistry

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