Emission transitions in the Paschen series end at orbit n = 3 and start from orbit n and can be represented as v = 3 .29 × 10 15 ( Hz ) 1 3 2 – 1 n 2 . Calculate the value of n if the transition is observed at 1285 nm . Find the region of the spectrum.

Given: Wavelength of transition = 1285 nm = 1285 × 10 - 9 m ν = 3 .29 × 10 15 1 3 2 - 1 n 2 Since, ν = c λ = 3 × 10 8 ms - 1 1285 × 10 - 9 m Now, ν = 2 .33 × 10 14 s - 1 3 .29 × 10 15 1 9 - 1 n 2 = 2 .33 × 10 14 1 9 - 1 n 2 = 2 .33 × 10 14 3 .29 × 10 15 1 9 - 0 .7082 × 10 - 1 = 1 n 2 ⇒ 1 n 2 = 1 .1 × 10 - 1 - 0 .7082 × 10 - 1 1 n 2 = 4 .029 × 10 - 2 n = 14.029 × 10 - 2 n = 4 .98 n = 5 Hence, for the transition to be observed at 1285 nm , n = 5 . The spectrum lies in the infra-red region.

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The longest wavelength doublet absorption transition is observed at $589$ and $589.6 nm .$ Calculate the frequency of each transition and energy difference between two excited states.

Important Questions on Structure of Atom

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Textbook for Class XI Chemistry Part I>Chapter 2 - Structure of Atom>EXERCISES>Q 2.51

The work function for caesium atom is $1 .9 eV$ . Calculate (a) the threshold wavelength and (b) the threshold frequency of the radiation. If the caesium element is irradiated with a wavelength $500 nm,$ calculate the kinetic energy and the velocity of the ejected photoelectron.

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Textbook for Class XI Chemistry Part I>Chapter 2 - Structure of Atom>EXERCISES>Q 2.52

Following results are observed when sodium metal is irradiated with different wavelengths. Calculate (a) threshold wavelength and, (b) Planck's constant.

$λ (nm)$	$500$	$450$	$400$
$v \times 10^{- 5} (cm s^{- 1})$	$2.55$	$4.35$	$5.35$

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Textbook for Class XI Chemistry Part I>Chapter 2 - Structure of Atom>EXERCISES>Q 2.53

The ejection of the photoelectron from the silver metal in the photoelectric effect experiment can be stopped by applying the voltage of

0 .35 V

when the radiation

256 .7 nm

is used. Calculate the work function for silver metal.

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Textbook for Class XI Chemistry Part I>Chapter 2 - Structure of Atom>EXERCISES>Q 2.54

If the photon of the wavelength

150 pm

strikes an atom and one of its inner bound electrons is ejected out with a velocity of

1 .5 \times 10^{7} {ms}^{- 1},

calculate the energy with which it is bound to the nucleus.

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11th CBSE

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Textbook for Class XI Chemistry Part I>Chapter 2 - Structure of Atom>EXERCISES>Q 2.55

Emission transitions in the Paschen series end at orbit

n = 3

and start from orbit

n

and can be represented as

v = 3 .29 \times 10^{15} (Hz) [\frac{1}{3^{2}} - \frac{1}{n^{2}}]

. Calculate the value of n if the transition is observed at

1285 nm

. Find the region of the spectrum.

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11th CBSE

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Textbook for Class XI Chemistry Part I>Chapter 2 - Structure of Atom>EXERCISES>Q 2.56

Calculate the wavelength for the emission transition if it starts from the orbit having radius

1 .3225 nm

and ends at

211 .6 pm .

Name the series to which this transition belongs and the region of the spectrum.

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11th CBSE

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Textbook for Class XI Chemistry Part I>Chapter 2 - Structure of Atom>EXERCISES>Q 2.57

Dual behavior of matter proposed by de Broglie led to the discovery of electron microscope often used for the highly magnified images of biological molecules and other type of material. If the velocity of the electron in this microscope is

1 .6 \times 10^{6} {ms}^{- 1},

calculate de Broglie wavelength associated with this electron.

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11th CBSE

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Textbook for Class XI Chemistry Part I>Chapter 2 - Structure of Atom>EXERCISES>Q 2.58

Similar to electron diffraction, neutron diffraction microscope is also used for the determination of the structure of molecules. If the wavelength used here is

800 pm

, Calculate the characteristic velocity associated with the neutron.

The longest wavelength doublet absorption transition is observed at 589 and 589.6 nm. Calculate the frequency of each transition and energy difference between two excited states.

Important Questions on Structure of Atom

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The longest wavelength doublet absorption transition is observed at $589$ and $589.6 nm .$ Calculate the frequency of each transition and energy difference between two excited states.