Structure of Atom — practice questions

158 curated practice questions from Structure of Atom (Chemistry NEET, NTA Exams) — 39 hard, 67 easy, 52 medium. Every question includes the final answer free; step-by-step worked solutions with a free account.

• Given below are two statements: One is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A)…
• Given below are two statements: One is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A)…
• Given below are two statements. One is labelled as Assertion and the other is labelled as Reason. STATEMENT- 1…
• The orbital angular momentum for an electron revolving in an orbit is given by I(I+1) h 2 . This momentum for an…
• Which of the following has the maximum number of unpaired 'd' electrons?
• Up to what maximum potential will a copper ball, remote from all other bodies, be charged when irradiated by…
• A particle executing simple harmonic motion of amplitude 5 cm has maximum speed of 31.4 cm/s. The frequency of its…
• Light of frequency 1.5 times the threshold frequency is incident on a photosensitive material. If the frequency is…
• If work function of a metal is 4.2 eV, the cut-off wavelength is
• The ground state energy of hydrogen atom is -13.6 eV. The energy of second excited state He + ion in eV is:
• If rDNA was inserted at recognition site of tetracycline in pBR322 plasmid. Which statement is correct regarding the…
• The work function of a photoelectric material is 3.3 eV. The threshold frequency is
• The 71 st electron of an element X with an atomic number of 71 enters into the orbital :
• The ratio of the energy of a photon of 200 A wavelength radiation to that of 4000 A radiation is:
• A radio transmitter operates at a frequency of 880 kHz and a power of 10 kW. The number of photons emitted per sec are
• The use of photoelectric cell depends upon the fact that the number of electrons produced is proportional
• Assertion : When certain wavelength of light falls on metal surface it ejects electron. Reason : Light was wave nature.
• Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A)…
• What hydrogen-like ion has the wavelength difference between the first line of Balmer and Lyman series equal to 59.3…
• The number of radial nodes in the 3p probability density distribution is:
• The threshold frequency for a metallic surface corresponds to energy of 6.2 eV and the stopping potential for a…
• What transition in He + ion shall have the same wave number as the first line in Balmer series of hydrogen atom?
• A particle of mass M at rest decay into two particles of masses m 1 and m 2 having non-zero velocities. The ratio of…
• Light of wavelength 4000 A is incident on a metal whose work function is 2 eV. The maximum kinetic energy of…
• The photoelectric current stops when the collecting wire in the photocell is one volt negative with respect to the…
• The electronic configuration of element with atomic number 24 is:
• If the kinetic energy of a free electron doubles, its de-Broglie's wavelength changes by the factor
• In Bohr's theory, the radius r of an orbit is proportional to:
• The time taken for one revolution in the n th orbit of hydrogen atom at radius r is:
• Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A)…
• The stopping potential as a function of frequency of incident radiation is plotted for two different photoelectric…
• The work function of a metallic surface is 5.01 eV. Photoelectrons are emitted when light of wavelength 2000 a A falls…
• Which one of the following will be deflected in an electric field ?
• The threshold wavelength for photoelectrons emission from a material is 5200 a a Photoelectrons will be emitted when…
• The velocity of the photo-electrons emitted in the photoelectric effect depends only on:
• The de-Broglie's wavelength of a proton (charge = 1.6 x 10 -19 C, mass = 1.6 x 10 -27 kg) accelerated through a…
• Suppose an electron is attracted towards the origin by a force (k / r) where (k) is a constant and (r) is the distance…
• The potential difference that must be applied to stop the fastest photoelectrons emitted by a nickel surface, having…
• A radiation of energy E falls normally on a perfectly reflecting surface. The momentum transferred to the surface is
• Electromagnetic radiation of wavelength =0.30 ~m falls on a photocell operating in the saturation mode. The…
• To increase the kinetic energy of ejected photo-electrons, we need to increase
• The work function for Aluminium is 4.125 eV. The cut-off wavelength for photoelectric effect for Aluminium will be:
• When a piece of metal is illuminated by a monochromatic light of wavelength λ, then stopping potential is 3V s . When…
• Heat treatment of muscular pain involves radiation of wavelength of about 900 nm. Which spectral line of H-atom is…
• A spherical solid ball of volume V is made of material of density ρ 1 . It is falling through a liquid of density ρ 2…
• Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A)…
• How many unpaired electrons are present in Ni 2 + ?
• The relationship between energy E, of the radiation with a wavelength 800 A and the energy of radiation with a…
• The maximum velocity of an electron emitted by light of wavelength (λ) incident on the surface of a metal of work…
• The radius of which of the following orbit will be double the radius of the first Bohr's orbit of hydrogen atom?
• A nuclide of an alkaline earth metal undergoes radioactive decay by emission of three α-particles in succession. The…
• In a photoelectric experiment the factors which is determined by the frequency of incident radiation is
• Which one of the following is not different for an atom and its corresponding ion?
• The ratio of the diameter of an atom to the diameter of its nucleus is about 10 4. Considering the density of ordinary…
• The maximum kinetic energy of the emitted photoelectrons in photoelectric effect is independent of:
• Two identical metal plates show photoelectric effect. Light of wavelength λ A falls on plate A and λ B falls on B…
• If a source of power 4 kW produces 10 20 photons/second, the radiation belongs to a part of the spectrum called
• The photoelectric threshold wavelength of silver is 3250 10^ -11 ~m . The velocity of the electron ejected from a…
• The total energy of an electron in the first excited state of hydrogen is about — 3.4 eV. Its kinetic energy in this…
• An element 'X' on emitting an α-particle does not change its group number in the periodic table. The element is:
• The electrons, identified by quantum numbers n and I , (i) n = 4, I = 1, (ii) n = 4, I = 0, (iii) n = 3, I = 2, and…
• The ground state energy of Hydrogen atom is — 13.6 eV. When its electron is in the first excited state, its excitation…
• When the electron of a hydrogen atom jumps from n = 4 to n = 1 state, the number of spectral lines emitted is:
• The ionization energy of Li 2 + is equal to
• The photoelectric threshold wavelength for potassium (work function being 2 eV) is (Take, h=6.6 10^ -34 5 )
• Photon of frequency (f) has a momentum associated with it. If c is the velocity of light, the momentum is
• Which one of the following ions has electronic configuration [Ar] 3d 6 ? ( At. no: Mn = 25, Fe = 26, Co = 27, Ni = 28)
• Photoelectrons emitted from a metallic surface are those which are:
• If Hund's rule is not followed, magnetic moment of Fe 2 + , Mn + and Cr all having 24 electrons will be in the order:
• The number of allowed values of magnetic quantum numbers for a given value of azimuthal quantum number I is:
• The frequency and the intensity of a beam of light falling on the surface of a photoelectric material are increased by…
• A light of wavelength λ 1 is incident on a photoelectric plate. It is found that for certain potential difference the…
• The kinetic energy of most energetic electrons emitted from a metallic surface is doubled when the wavelength (λ) of…
• If binding energy of an electron in a hydrogen atom is 13.6 eV, the energy required to remove the electron from the…
• The mass of proton is 1.0073 u and that of neutron is 1.0087 u (u = atomic mass unit ). The binding energy of _ 2 He ^…
• Hydrogen atom from excited state comes to the ground state by emitting a photon of wavelength λ. If R is the Rydberg…
• When a particular metallic surface is illuminated with monochromatic light of wavelength λ the stopping potential for…
• The threshold frequency for a certain metal is f 0 . When light of frequency f = 2f 0 is incident on it, the maximum…
• The frequency of an electron moving in 3 rd orbit of He + ion is:
• The wavelength associated with golf ball weighing 200 g and moving at a speed of 5 m/h is of the order:
• Ionisation energy of He + is 19.6 × 10 -18 J atom -1 . The energy of the first stationary state (n = 1) of Li 2+ is:
• The photons in a radiowave of wavelength 3 x 10 4 cm have energy
• Which of the following series of transitions in the spectrum of hydrogen atom fall in visible region?
• Which of the following transitions in hydrogen atoms emit photons of highest frequency?
• A proton is accelerated to one tenth the speed of light. Its speed can be measured with a precision of 1%. Its…
• If the shortest wavelength of H atom in Lyman series is x, then longest wavelength in Balmer series of He + is:
• A beam of ultraviolet light of wavelength 300 nm and intensity 1.0 watt/m 2 falls on the surface of a photo sensitive…
• When yellow light is incident on a surface, no electrons are emitted while with green light emission of electrons is…
• The work functions of Caesium (Cs), Potassium (K) and Sodium (Na) are 2.14 eV, 2.30 eV and 2.75 eV respectively. If…
• The electron in a hydrogen atom makes a transition from an excited state to the ground state. Which of the following…
• In photoelectric emission process from a metal of work function 1.8 eV, the kinetic energy of most energetic electrons…
• An element with atomic number 9 emits K_ n X-rays of wavelength λ. The atomic number of the element which emits K_ n…
• If a 0 is the radius of first Bohr orbit of H-atom and 6πa 0 is the de-Broglie wavelength of n th orbit of hydrogen…
• Two identical photo cathode receive light of frequencies f 1 and f 2 . If the velocities of the photoelectrons (of mass…
• The ionization potential of hydrogen is 13.6 eV. Then the energy released when an electron jumps from n = 3 to n = 2…
• The uncertainty in the calculation of 2 nd Bohr orbit radius is 10% for helium atom then the uncertainty in velocity of…
• When the sun shines on your hands, your hands get warm because :
• How far from the nucleus is the electron in a hydrogen atom if it has energy of -0.850 eV?
• A photocell is illuminated by a small bright source placed 1 m away. When the same source of light is placed 1 2 m…
• When two monochromatic lights of frequency, and v 2 are incident on a photoelectric metal, their stopping potential…
• An X-ray tube produces a continuous spectrum of radiation with its shortest wavelength of 45 x 10 -2 A . The maximum…
• When an electron jumps from 2 nd orbit to 1 st orbit then the wave number = v _ 1 and when it jumps from 3 rd to 2 nd…
• A particle is moving 5 times as fast as an electron. The ratio of the de-Broglie wavelength of the particle to that of…
• The shortest wavelength in hydrogen spectrum of Lyman series when R H = 109678 cm -1 is:
• What is the maximum number of orbitals that can be identified with the following quantum numbers? n = 3, l = 1, m l = 0
• When electronic transition occurs from higher energy state to a lower state with energy difference equal to ΔE electron…
• A nucleus represented by the symbol Z _ 2 X has:
• In an atom, an electron is moving with a speed of 600 m s -1 with an accuracy of 0.005%. Certainty with which the…
• If an electron and a proton have the same de-Broglie's wavelength, then the kinetic energy of the electron is
• Uncertainty in the position of an electron (mass = 9.1 × 10 -31 kg) moving with a velocity 300 ms -1 , accurate upto…
• The quantum numbers + 1 2 and - 1 2 for the electron spin represent:
• The ratio of the wavelengths of last lines of Balmer and Lyman series is:
• The wave number of the spectral line in the emission spectrum of hydrogen will be equal to 8 9 times the Rydberg…
• The work function of a surface of a photosensitive material is 6.2 eV. The wavelength of the incident radiation for…
• The retarding potential necessary to stop the emission of photo-electrons, when a target material of work function 1.24…
• Which of the following sets of quantum numbers is not allowed?
• The concept of quantum nature of light has emerged to explain
• For silver metal, threshold frequency for the emission of photoelectron is 1.13 × 10 17 s -1 . The kinetic energy of…
• Assertion : When certain wavelength of light falls on metal surface it ejects electron. Reason: Light has wave nature.
• In manganese atom, Mn (Z = 25), the total number of orbitals populated by one or more electrons (in ground state) is:
• The energy of the electron in the nth orbit of hydrogen atom is given as: E_ n =- 1311.8 n^ 2 ~kJ ~mol ^ -1 What is the…
• An electron is allowed to move freely in a closed cubic box of length 10 cm. The maximum uncertainty in its velocity…
• A photoelectric surface is illuminated successively by monochromatic light of wavelength and 2 . If the maximum kinetic…
• An element recently discovered is Uub. Expected electronic configuration of the element is:
• Yellow light is of wavelength 6000 a A . The number of photons emitted per sec by yellow lamp radiating a power of 10…
• Given below are two statements: One is labelled as Assertion (A) and the other is labeled as Reason (R). Assertion (A)…
• If the atom 257 Fm follows Bohr's model and the radius of 257 Fm is (n) times the Bohr radius, then the value of n is
• A 200 W sodium street lamp emits yellow light of wavelength 0.6 μ m. Assuming it to be 25% efficient in converting…
• The number of d-electrons in Fe 2+ (Z = 26) is not equal to the number of electrons in which one of the following?
• If the de Broglie wavelength of the electron in nth Bohr orbit in a hydrogenic atom is equal to 1.5 πa 0 (a 0 is Bohr…
• The ratio of the difference in energy between the first and the second Bohr orbit to that between second and third Bohr…
• For any electron, the direction of magnetic moment is .......... to the orbital angular momentum, but magnitude is…
• The ionization potential of hydrogen atom is — 13.6 eV. An electron in the ground state of a hydrogen atom absorbs a…
• In photoelectric effect, the number of electrons ejected per second is:
• Light with an energy flux 25 10^ 4 Wm ^ -2 falls on a perfectly reflecting surface at normal incidence. If the surface…
• In hydrogen spectrum, the shortest wavelength in the Balmer series is . The shortest wavelength in the Bracket series…
• Monochromatic light of frequency 6.0 10^ 14 Hz is produced by a laser. The power emitted is 2 10^ -3 W. The number of…
• A strong argument for the particle nature of cathode rays is that they
• A metal surface is illuminated one by one by photons of energy 1 eV and 2.5 eV respectively. The work function of the…
• The work function of a photoelectric material is 3.3 eV. Its threshold frequency will be:
• An atom absorbs energy of 1 eV. In the spectrum of this atom, where would be a missing wavelength?
• Balmer gives an equation for wavelength of visible radiation of hydrogen (H) spectrum as l = k n^ 2 n^ 2 -4 The value…
• For emission line of atomic hydrogen from n i = 8 to n f =n, the plot of wave number ( v ) against ( 1 n^ 2 ) will be…
• A light of wavelength 280 nm is used in an experiment on photoelectric surface of lithium ( C =2.5 eV ) as cathode. The…
• A broken ligament is being 'welded' back in place using 20 ms pulse from a 0.5 W laser operating at a wavelength of 632…
• Consider the ground state of Cr atom (Z = 24). The number of electrons with the azimuthal quantum numbers, I = 1 and 2…
• In the Bohr model of the hydrogen atom, let R, V and E represent the radius of the orbit, speed of the electron and…
• Given below are two statements Statement I : Bohr had to postulate that the electrons in stationary orbits around the…
• Find the orbital angular momentum of an electron having quantum numbers: n=3, I=2, m_ I =0, m_ I =- 1 2
• Sodium and Copper have work functions 2.3 eV and 4.5 eV respectively. Then, the ratio of their threshold wavelengths is…
• The surface of a metal is illuminated by the light of wavelength 400 nm. The kinetic energy of the ejected…
• The radii of two of the first four Bohr's orbits of hydrogen atom are in the ratio 1:4. The energy difference between…
• Electrons in a certain energy level n = n 1 , can emit 3 spectral lines. When they are in another energy level n = n 2…
• The number of d-electrons retained in Fe 2 + (Atomic number of Fe = 26) ions is:
• One requires 11 eV of energy to dissociate a carbon monoxide molecule into carbon and oxygen atoms. The minimum…
• The energy required to break one mole of Cl-Cl bonds in Cl 2 is 242 kJ mol -1 . The longest wavelength of light capable…
• The transition from the state n = 4 to n = 3 in a hydrogen-like atom results in ultraviolet radiation. Infrared…
• The orbital angular momentum of an electron in 2s-orbital is:

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