Page 1 : 1. Cathode rays are rays moving from cathode to anode. Give any two properties of, cathode rays., 2. Canal rays were discovered by discharge tube experiments conducted in a, modified cathode ray tube. Give any two characteristics of canal rays., 3. What are the important observations and conclusions made by Rutherford from his, alpha ray scattering experiment? Give any two limitations of Rutherford’s nuclear, model of atom., 4. The number of protons, electrons and neutrons in a species are equal to 17, 18 and 18, respectively. Represent the proper symbol of this species?, 5. Mention two observations which could not be explained by wave nature of, electromagnetic radiations., 6. Write two important results observed during photoelectric effect., 7. The threshold frequency for a metal is 7.0 x 1014 s-1. Calculate the kinetic, energy of an emitted electron when radiation of frequency (ν), 1.0 x, 15, 10 s-1 hits the metal., 8. The number of electrons ejected in the photoelectric effect is proportional to, ………….. of light used. (frequency, intensity), 9. Calculate the wavelength of the first line in Lyman series of the hydrogen, spectrum (R = 109677 cm-1), 10. The Balmer series of lines in the hydrogen spectrum appear in the visible region, of the electromagnetic spectrum. Calculate the wave number of the second line in, the Balmer series. (Rydberg constant for Hydrogen is 109677 cm-1), 11. Find the maximum number of emission lines, when the excited electron of the, hydrogen atom in n =6, drops to the ground state (n = 1)., 12. Give the postulates of Bohr model of hydrogen atom. Also write two merits and two, limitations of this model., 13. Calculate the radius of the second orbit of Li2+. (Express answer in nm)., 14. a) State the dual behaviour of matter. ( b) A moving electron has a de Broglie, wavelength of 7 x 10–7 m. Calculate its kinetic energy. (Planck’s constant = 6.626, x 10-34 Js, mass of an electron = 9.1 x 10-31 kg), 15. A photon has a wavelength of 3.5 A0. Calculate its mass (Given h = 6.626 x 10-34 Js., Velocity of light = 3 x 108 m/s), 16. State Heisenberg’s uncertainty principle? Give the mathematical representation of, Heisenberg’s uncertainty principle and its one important significance., 17. An electron is moving with a velocity of 2.5 x 106 m/s. lf the uncertainty in its velocity is, 0.1%. Calculate the uncertainty in its position. (Planck’s constant, h = 6.626 x 10-34 Js., Mass of the electron = 9.1 x 10-31 kg)., 18. A microscope with suitable photons is employed to locate an electron in an, atom within a distance of 0.4 A0. What is the uncertainty involved in the, measurement of its velocity?, 19. Explain quantum numbers. Give the importance of quantum numbers in Pauli’s, Exclusion Principle., 20. Name the quantumokv number which gives the spatial orientation of an orbital with, respect to standard cc set of co-ordinate axes.

Page 2 : 21. a) Represent the orbital with quantum numbers n the = 5 and l = 3., b)How many angular nodes are present in a 5f-orbital?, c), Represent the orbital with quantum numbers n = 1 and l = 0, d), Quantum number gives the address of electrons. Explain the quantum number, which determines: i) Distance of electron from nucleus. ii) The orbital angular, momentum of an electron., e) Represent the orbitals given below: i) n = 1, l = 0, 2 ii) n = 2, l = 1, 22. Write the subshell-wise electronic configurations of the following elements: i) Cu (Z, = 29),, ii) Cr (Z = 24) give reason for the extra stability of these, atoms., 23. State the rules behind the electronic configuration in an atom., 24. . Represent graphically, the variation of probability density (ψ2(r)) as a function of, distance (r) of the electron from the nucleus for 1s and 2s orbitals., 25. Draw the shapes of s and p orbitals