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1. Which fundamental particle was discovered by J.J. Thomson in 1897? [1]
   A) Proton

   B) Neutron

   C) Electron

   D) Alpha particle
2. The mass of a proton is approximately how many times that of an electron? [1]
   A) 1000

   B) 1840

   C) 2000

   D) 500
3. Which isotope of Uranium is used in nuclear reactors? [1]
   A) U-238

   B) U-235

   C) U-234

   D) U-239
4. The atomic number (Z) of an atom represents the number of: [1]
   A) Neutrons

   B) Protons

   C) Positron

   D) Photons
5. What is the velocity of electromagnetic radiation in vacuum? [1]
   A) \(3.0 \times 10^7 \, \text{m/s}\)

   B) \(3.0 \times 10^8 \, \text{m/s}\)

   C) \(3.0 \times 10^9 \, \text{m/s}\)

   D) \(3.0 \times 10^6 \, \text{m/s}\)
6. The energy of a photon is proportional to its: [1]
   A) Wavelength

   B) Frequency

   C) Amplitude

   D) Velocity
7. Which series of hydrogen spectrum lies in the visible region? [1]
   A) Lyman

   B) Balmer

   C) Paschen

   D) Pfound
8. The "Plum Pudding" model of an atom was proposed by: [1]
   A) Rutherford

   B) Bohr

   C) Thomson

   D) Dalton
9. Which shell is known as the valence shell? [1]
   A) Inner most

   B) Middle

   C) Outer most

   D) Nucleus
10. The bond formed by the transfer of electrons is called: [1]
    A) Covalent

    B) Ionic

    C) Hydrogen

    D) Metallic
11. Which molecule contains a triple bond? [1]
    A) \(H_2\)

    B) \(O_2\)

    C) \(N_2\)

    D) \(Cl_2\)
12. The shared pair of electrons in a coordinate covalent bond is contributed by: [1]
    A) Both atoms

    B) Only one atom

    C) Neither atom

    D) Three atoms
13. Which theory explains the geometry of molecules based on electron pair repulsion? [1]
    A) Bohr's Theory

    B) VSEPR Theory

    C) Dalton's Theory

    D) Lewis Theory
14. A polar covalent bond is formed between atoms with: [1]
    A) Same electronegativity

    B) Different electronegativity

    C) Same mass

    D) Different mass
15. What is the SI unit of dipole moment? [1]
    A) Debye

    B) Coulomb-metre

    C) Newton

    D) Joule
16. The "Octet Rule" states that atoms tend to have how many electrons in their valence shell? [1]
    A) 2

    B) 4

    C) 6

    D) 8

17. Define Atomic Number and Mass Number. Give their relationship. [2]
18. What are Isotopes? Give examples of two isotopes of Uranium. [2]
19. Briefly describe Thomson's plum pudding model of an atom. [2]
20. Why did Rutherford's model fail to explain the stability of an atom? [2]
21. Define Wavelength \( (\lambda) \) and Frequency \( (\nu) \) of electromagnetic radiation. [2]
22. Calculate the energy of a photon with frequency \( 1.2 \times 10^{10} \, \text{Hz} \). (Given \( h = 6.626 \times 10^{-34} \, \text{J}\cdot\text{s} \)) [2]
23. What is a line spectrum? How does it differ from a continuous spectrum? [2]
24. Name the five series of emission lines observed in the hydrogen spectrum. [2]
25. State any two postulates of Bohr's atomic model. [2]
26. What is a chemical bond? Why do atoms combine to form a molecule? [2]
27. Explain the formation of \( Na^+ \) and \( Cl^- \) ions from their respective atoms. [2]
28. Define Lattice Energy and its role in the stability of ionic compounds. [2]

29. What is an Alpha particle and what is its charge? [2]
30. Define Wave Number \( (\overline{\nu}) \) and state its relation with Wave Length. [2]
31. What is the difference between a 'quantum' and a 'photon'? [2]
32. What are Valence Electrons? Identify the valence electrons in Nitrogen. [2]
33. Write the Lewis dot symbols for Lithium and Oxygen atoms. [2]
34. Define Covalent Bond with one example. [2]
35. What is a Lone Pair of electrons? Give an example from ammonia molecule. [2]
36. Give two examples of molecules containing Coordinate Covalent bonds. [2]
37. What is Dipole Moment? State its SI unit. [2]

38. Describe Rutherford's Gold Foil experiment. What were the three main conclusions drawn from it? [3]
39. Explain the Born-Haber cycle for the formation of sodium chloride (NaCl) with a diagram. [3]
40. Compare any three characteristic properties of Ionic and Covalent compounds. [3]
41. What is VSEPR theory? How does it help in predicting the geometry of a molecule like \( H_2O \)? [3]

42. Discuss Bohr's model of the atom in detail. Explain how it accounts for the existence of different series of lines in the hydrogen spectrum. [5]
43. Explain the concept of Hybridization. Illustrate the process for \( sp, sp^2, \) and \( sp^3 \) hybridization with suitable examples. [5]