MODEL COLLEGE ASSIGNMENT SHEET FOR STRUCTURE OF ATOM. What are the main postulates of Bohr s theory of an atom?. Explain how the angular momentum of an electron in an atom is quantized? 3. What are the various merits of Bohr s atomic model? 4. Explain the limitations or drawbacks of Bohr s theory of an atom. Explain the term subshell. 5. Explain de-broglie equation (relationship). 6. Discuss the dual nature of electrons 7. What are quantum numbers? 8. Explain the need of quantum number? 9. Describe the shape of s-orbital. 0. Describe the shapes of p-orbitals.. Explain the shapes of d-orbitals.. Define : (i) Spherical (radial) nodes (ii) Nodal plane. 3. Using s, p, d, f notations, describe the orbital following quantum numbers. (i) n = 4, = 0 (ii) n = 5, = 3 4. Write electronic configurations of the elements (number in the brackets indicate atomic numbers) (i) Helium () (ii) Boron (5) (iii) Nitrogen (7) (iv) Sodium () (v) Silicon (4) (vi)chlorine (7) (vii) Potassium (9) (viii) Oxygen (8) 5. How many protons, electrons and neutrons are there in the following nucleus? (i) 7 O 5 80 8 (ii) Mg (iii) 35 Br 6. The number of electrons, protons, and neutrons in a species are equal to 8, 6 and 6 respectively. Assign proper symbol to the species.
7. Complete the following table : Serial Number Particle Mass Number (A) Atomic Number (Z) Protons Neutrons Electrons i O - 8-8 - ii Al 7 - - - 3 iii iv Cl 35-7 - - Mg - - - 0 8. Write the complete symbol for the atom with the given atomic number (Z) and atomic mass (A) : (i) Z = 7, A = 35 (ii) Z = 9, A = 33 (iii) Z = 4, A = 9 9. Calculate the mass and charge of one mole of electrons. 0. Calculate the number of electrons which will together weigh one gram. 4. Calculate the total number and the total mass of neutrons in 7 mg of C 7 (assume the mass of a neutron =.675 0 kg).. An element with mass number 8 contains 3.7% more neutrons as compared to protons. Assign the atomic symbol. 3. An ion with mass number 56 contains 3 units of positive charge and 30.4% more neutrons than electrons. Assign the symbol for the ion. 4. How many electrons, protons and neutrons are present in each of the following? (i) 37 56 Ba (ii) 9 6 9 F (iii) 88 Ra 5. From the following nuclei select the isotopes and isobars : 38 9 U, 34 90 U, 34 9 Pa 6. How many neutrons and protons are there in the following nuclei : (i) (iv) 6 O 3 4 8 (ii) 6 C (iii) Mg 88 Sr 56 38 (iv) 6 Fe Type II : Problems based on dual nature of light 7. Yellow light emitted from a sodium lamp has a wavelength () of 580 nm. Calculate the frequency and wave number of this light.
8. A certain radio station broadcasts on a frequency of 980 k Hz (kilohertz). What is the wavelength of electromagnetic radiation broadcast by the radio station? 9. The wavelength range of the visible spectrum extends from violet (400 nm) to red (750 nm). Express these wavelengths in frequencies (Hz). 30. Electromagnetic radiation of wavelength 4 nm is just sufficient to ionize the sodium atom. Calculate the ionization energy of sodium in kj mol (h = 6.66 34 0 J s). 3. Calculate the minimum amount of energy that the photons must possess to eject electrons from caesium metal. The threshold frequency of caesium metal is 4.6 4 0. s (h = 6.63 0 34 Js) 3. Calculate the kinetic of the ejected electrons when ultra-violet radiation of frequency.6 0 5 s strikes the surface of potassium metal. Threshold frequency of potassium is 5 0 4 s. 33. The wavelength of a spectral line of caesium is 460 nm. Calculate the frequency of the line. 34. Calculate the wavelength, frequency and wave number of light wave whose time 0 period is.0 0 s. 35. Calculate the wave number of radiations having a frequency of 4 0 Hz. Type III : Problems based on de-broglie s Equation 36. A tennis ball of mass 6.0 0 kg is moving with a speed of 6 m s. Calculate the wavelength associated with this moving tennis ball. Will the movement of this ball exhibit a wave character? 37. Calculate de-broglie wavelength of an electron (mass = 9. 0 3 kg) 34 at % speed of light (h = 6.63 0 kgm s ) 38. Calculate the wavelength of an electron moving with a velocity of.05 0 7 ms. moving 39. Calculate the mass of a photon of sodium light having wavelength 5894 A and 8 velocity 3 0 m s. 40. What will be the wavelength of a ball of mass 0. kg moving with a velocity of 0 ms. 4. Calculate the mass of a photon of light having wavelength 3.6 A. 4. Calculate the momentum of a particle which has a de-broglie wavelength of 0. 0 34. nm (h = 6.63 Js)
Multiple Choice questions. transmuted one element into another through nuclear reaction, for the first time. Neils Bohr Albert Einstein Ernest Rutherford Sir J.J. Thomson. Introduction. The term atom was introduced by. Dalton Democritus Rutherford Einstein 3. showed that electricity could be passed through the electrolytes. Michael Faraday Max Planck J.J. Thomson Prout. 3. Discovery of electron 4. Electrons were discovered by. Ernest Rutherford Cesar Charles Neils Bohr Sir J.J. Thomson 5. Which of the following statement is NOT CORRECT regarding cathode rays? Cathode rays originate from the cathode Charge and masses of the particles constituting cathode rays depends upon the nature of the gas Charge and mass of the particles present does not depend upon the material of the cathode The ratio charge/mass of the particles is much greater than that of anode rays 4. Discovery of proton 6. The anode rays were discovered by. Goldstein Crooke Chadwick Thomson 7. Which of the following statements is INCORRECT regarding anode rays? Their e/m ratio is constant. They are deflected by electrical and magnetic field. They are produced by ionization of molecules of the residual gas. They originate from the anode.
6. Discovery of neutron and constitution of atomic nucleus 8. Neutron was discovered by. Rutherford J.J. Thomson Lord Chadwick Mosely 9. Which property of the element is a whole number? Atomic mass Mass number Atomic size Ionization potential 0. The value of positive charge present on the nucleus of an atom was determined by. Neils Bohr J.J. Thomson Chadwick Henry Mosely. The sum of numbers of protons and neutrons present in the nucleus of an atom is called of that atom. Mass number Atomic number Electron number None of these. 7. Isotopes and isobars. The isotopes of an element differ in. The number of neutrons in the nucleus The charge on the nucleus The number of extra-nuclear electrons Both the nuclear charge and the number of extra-nuclear electrons. 3. Isobars have the same. Atomic number Number of electrons Mass number Number of neutrons 35 37 4. 7 Cl and 7 Cl differ from each other in number of. Electrons Mesons Protons Nucleons 8. Atomic models 5. J.J. Thomson s model of atom is also called model. Plum pudding Solar Cake Quantum 9. Rutherford s atomic model 6. Rutherford s scattering experiments led to the discovery of. Nuclear model of an atom
Presence of neutrons in the nucleus Structure of electrons All of these. 7. In Rutherford s scattering experiment, which of the following does NOT happen? Most of the -rays pass through without deflection A few -particles pass through the nucleus Very few -particles are deflected through large angles Very very few of the -particles get deflected through an angle of 80. 8. Rutherford s alpha particle scattering experiment eventually led to the conclusion that. Mass and energy are related Electrons occupy space around the nucleus Neutrons are buried deep in the nucleus The point of impact with matter can be precisely determined 9. Quantum theory of radiation was put forward by. Einstein Fajan Max Planck Fermi 0. The value of Planck s constant is. 6.66 0 34 3 Js 6.03 0 Js 6.66 7 0 4 Js 6.66 0 Js. In hydrogen spectrum the series of lines appearing in ultraviolet region of electromagnetic spectrum are called. Lyman series Blamer series Pfund series Brackett series. Bohr s model failed because of the advent of. Planck s quantum theory Electromagnetic wave theory Heisenberg s uncertainty principle Photoelectric effect 3. The splitting of the spectral lines under the influence of magnetic field is called. Zeeman effect Crompton effect Photoelectric effect Diffraction. Concepts of shells and subshells 4. The maximum number of electrons in a subshell for which - 3 is. 4 0
8 4. Dual nature of matter and light 5. Distance between the consecutive crests or trough is called. Amplitude Frequency Wavelength Wave number 6. The equation E = h for the energy of a photon was put forward by. Einstein Planck Maxwell Schrodinger 7. Which of the following is NOT CORRECT according to Planck s quantum theory? Energy is emitted or absorbed discontinuously Energy of a quantum is directly proportional to its frequency A photon is also a quantum of light Energy less than a quantum can also be emitted or absorbed 8. According to photoelectric effect, the kinetic energy of the ejected electron is directly proportional to. Wavelength of light Intensity of light Frequency of light Velocity of incident radiation 3. de-broglie equation 9. The de Broglie wavelength associated with a material particle is. Directly proportional to energy Directly proportional to momentum Inversely proportional to momentum Inversely proportional to energy 30. The de Broglie equation suggests that an electron has. Particle nature Wave number Particle-wave nature Radiation behaviour 3. Heisenberg s uncertainly principle rules out the exact simultaneous measurement of of an electron. Probability and intensity Energy and velocity Charge density and radius Position and momentum 3. Which of the following is the most CORRECT expression for Heisenberg s uncertainty principle? h x. p 4 h x. p 4
h x. p 4 5. Concept of atomic orbitals h x. v 4 33. The probability of finding an electron at the nucleus is. Unity Zero Infinity Negative 6. Quantum numbers 34. No two electrons in an atom can have. The same principal quantum numbers The same azimuthal quantum numbers The same magnetic quantum numbers An identical set of quantum numbers 35. Magnetic quantum specifies. Size of orbitals Shape of orbitals Orientation of orbitals in space Nuclear stability 36. The quantum number which specifies the location as well as energy is. Principal quantum number Azimuthal quantum number Spin quantum number Magnetic quantum number 37. The maximum number of electrons that can be accommodated in seventh principal shell is. 4 8 49 98 38. An electron having an azimuthal quantum number = 3 is. s-electron p-electron d-electron f-electron 39. The correct set of quantum numbers for the unpaired electron of Cl atom is., 0, 0 + 3,,,,,, 3, 0, 0
40. Azimuthal quantum number gives. Number of subshell Shape of electron cloud Angular momentum of the electrons All of these. 7. Shapes of orbitals 4. p-orbitals have orientation. One Two Three Five 4. The number of nodes in a 4d-orbital is. 0 3 43. Which of the following orbitals does NOT exist? d x d y x z d xy d zx 44. pz -orbital has nodal plane/planes. Zero One Two Three 45. In which of the following electron distribution in ground state, the Hund s rule is violated? s p s p s p s p 46. In Aufbau principle, the word Aufbau. Represents the name of scientist who developed the principle Is a German word which means building up Is related to the energy of the electron Is related to angular momentum of the electron. 47. For the electron present in s orbital of helium atom, the correct set of valves of quantum numbers is.
, 0, 0, +/,, 0, +/,,, +/, 0, 0, +/ 48. Which of the following principle/rule limits the maximum number of electrons in an orbital to? Aufbau principle Pauli s exclusion principle Hund s rule of maximum multiplicity Heisenberg s uncertainty principle 49. Presence of three unpaired electrons in phosphorus atom can be explained by. Pauli s rule Uncertainty principle Aufbau s rule Hand s rule 9. Electronic configuration of elements 50. Electronic configuration of Ca is. 5 s s p 6 6 s p 3s 3p s s s,s p,p 3s 6,3s,3p 6,4s