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Why was a change in the Bohr Model of atom required? Due to which important development (s), concept of movement of an electron in an orbit was replaced by, the concept of probability of finding

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Why was a change in the Bohr Model of atom required? Due to which important development (s), concept of movement of an electron in an orbit was replaced by, the concept of probability of finding electron in an orbital? What is the name given to the changed model of atom?

दीर्घउत्तर
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उत्तर

The drawbacks of Bohr’s model were (i) it was unable to explain the spectra for multi-electron systems (ii) it could not explain the molecule formation through chemical bonds.

The two important developments that contributed significantly towards the change of concept of movement of an electron in an orbit was replaced by, the concept of probability of finding an electron in an orbital were (i) Dual nature of matter (ii) Uncertainty Principle.

Quantum mechanical model of the atom is the name of the new model.

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पाठ 2: Structure of Atom - Multiple Choice Questions (Type - I) [पृष्ठ २३]

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एनसीईआरटी एक्झांप्लर Chemistry [English] Class 11
पाठ 2 Structure of Atom
Multiple Choice Questions (Type - I) | Q 55 | पृष्ठ २३

संबंधित प्रश्‍न

State Bohr’s third postulate for hydrogen (H2) atom. Derive Bohr’s formula for the wave number. Obtain expressions for longest and shortest wavelength of spectral lines in ultraviolet region for hydrogen atom


What is the energy in joules, required to shift the electron of the hydrogen atom from the first Bohr orbit to the fifth Bohr orbit and what is the wavelength of the light emitted when the electron returns to the ground state? The ground state electron energy is –2.18 × 10–11 ergs.


Calculate the energy required for the process 

\[\ce{He^+_{(g)} -> He^{2+}_{(g)} + e^-}\]

The ionization energy for the H atom in the ground state is 2.18 ×10–18 J atom–1


If the velocity of the electron in Bohr’s first orbit is 2.19 × 106 ms-1, calculate the de Broglie wavelength associated with it.


  1. Using the Bohr’s model, calculate the speed of the electron in a hydrogen atom in the n = 1, 2 and 3 levels.
  2. Calculate the orbital period in each of these levels.

The numerical value of ionization energy in eV equals the ionization potential in volts. Does the equality hold if these quantities are measured in some other units?


The Bohr radius is given by  `a_0 = (∈_0h^2)/{pime^2}`. Verify that the RHS has dimensions of length.


A parallel beam of light of wavelength 100 nm passes through a sample of atomic hydrogen gas in ground state. (a) Assume that when a photon supplies some of its energy to a hydrogen atom, the rest of the energy appears as another photon. Neglecting the light emitted by the excited hydrogen atoms in the direction of the incident beam, what wavelengths may be observed in the transmitted beam? (b) A radiation detector is placed near the gas to detect radiation coming perpendicular to the incident beam. Find the wavelengths of radiation that may be detected by the detector.


When a photon is emitted by a hydrogen atom, the photon carries a momentum with it. (a) Calculate the momentum carries by the photon when a hydrogen atom emits light of wavelength 656.3 nm. (b) With what speed does the atom recoil during this transition? Take the mass of the hydrogen atom = 1.67 × 10−27 kg. (c) Find the kinetic energy of recoil of the atom.


Radiation from hydrogen discharge tube falls on a cesium plate. Find the maximum possible kinetic energy of the photoelectrons. Work function of cesium is 1.9 eV.


Calculate angular momentum of an electron in the third Bohr orbit of a hydrogen atom.


The energy associated with the first orbit of He+ is ____________ J.


The energy of an electron in an excited hydrogen atom is - 3.4 eV. Calculate the angular momentum of the electron according to Bohr's theory. (h = 6.626 × 10-34 Js)


When an electric discharge is passed through hydrogen gas, the hydrogen molecules dissociate to produce excited hydrogen atoms. These excited atoms emit electromagnetic radiation of discrete frequencies which can be given by the general formula

`bar(v) = 109677 1/n_1^2 - 1/n_f^2`

What points of Bohr’s model of an atom can be used to arrive at this formula? Based on these points derive the above formula giving description of each step and each term.


Consider aiming a beam of free electrons towards free protons. When they scatter, an electron and a proton cannot combine to produce a H-atom ______.

  1. because of energy conservation.
  2. without simultaneously releasing energy in the from of radiation.
  3. because of momentum conservation.
  4. because of angular momentum conservation.

Use Bohr's postulate to prove that the radius of nth orbit in a hydrogen atom is proportional to n2.


A hydrogen atom in its first excited state absorbs a photon of energy x × 10-2 eV and exited to a higher energy state where the potential energy of electron is -1.08 eV. The value of x is ______.


The electron in a hydrogen atom first jumps from the third excited state to the second excited state and subsequently to the first excited state. The ratio of the respective wavelengths, λ12, of the photons emitted in this process is ______. 


In hydrogen atom, transition from the state n = 6 to n = 1 results in ultraviolet radiation. Infrared radiation will be obtained in the transition ______.


On the basis of Bohr's theory, derive an expression for the radius of the nth orbit of an electron of hydrogen atom.


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