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26. The maximum number of electrons that can occupy the shell with n = 3 is

A. 8 B. 10 C. 18 D. 32 E. 6

27. For an electron in a 3d orbital, the azimuthal quantum number l is

B. 1 C. 2 D. 3 E. 4

28. The ground state electronic configuration of chromium (Z = 24) is

A. [Ar] 3d4 4s2 B. [Ar] 3d5 4s1 C. [Ar] 3d6 D. [Ar] 4s2 4p4 E. [Ar] 3d3 4s3

29. Rutherford's gold foil experiment established the existence of

A. the electron B. the neutron C. a small dense positively charged nucleus D. energy levels E. orbitals

30. The energy of a photon of frequency nu is given by

A. h/nu B. h nu C. nu/h D. h nu2 E. h/nu2

31. The shape of a p orbital is

A. spherical B. dumb bell C. double dumb bell D. tetrahedral E. planar triangular

32. Hund's rule requires that

A. electrons pair up before occupying empty degenerate orbitals B. degenerate orbitals are singly occupied with parallel spins before pairing C. the lowest energy orbital is filled last D. no two electrons can have the same spin E. d orbitals fill before s orbitals of the same shell

33. The bond angle in a molecule with sp3 hybridization and no lone pairs is

A. 90 degrees B. 104.5 degrees C. 107 degrees D. 109.5 degrees E. 120 degrees

34. The dipole moment of carbon dioxide is zero because the molecule is

A. non-polar in its bonds B. linear and symmetrical C. angular D. tetrahedral E. ionic

35. The shape of the ammonia molecule according to VSEPR theory is

A. trigonal planar B. tetrahedral C. trigonal pyramidal D. linear E. bent with 104.5 degrees

36. As bond order increases, the bond length

A. increases B. decreases C. remains constant D. first increases then decreases E. becomes zero

37. A coordinate covalent bond is present in

A. methane B. the ammonium ion C. sodium chloride D. chlorine E. ethene

38. The ionic character of a bond increases with

A. decreasing electronegativity difference B. increasing electronegativity difference C. increasing bond order D. decreasing atomic size only E. increasing covalent radius

39. In benzene, all six carbon to carbon bonds are of equal length because of

A. sp3 hybridization B. resonance delocalization C. hydrogen bonding D. free rotation E. ionic character

40. The hybridization of carbon in ethyne is

A. sp3 B. sp2 C. sp D. sp3d E. unhybridized

41. For an exothermic reaction, the enthalpy change is

A. positive B. negative C. zero D. always equal to the activation energy E. undefined

42. Hess's law states that the enthalpy change of a reaction

A. depends on the path taken B. is independent of the path taken C. is always negative D. equals the activation energy E. depends only on temperature

43. The standard enthalpy of formation of an element in its most stable form is

A. always negative B. always positive C. zero D. equal to its atomization energy E. equal to its bond energy

44. The enthalpy of neutralization of a strong acid by a strong base is nearly constant because

A. all acids have the same concentration B. the reaction is always the combination of H+ and OH- to give water C. the salts formed are identical D. water is a catalyst E. the reaction is endothermic

45. The lattice energy of an ionic compound is determined indirectly using the

A. Born Haber cycle B. Carnot cycle C. Haber process D. Kelvin scale E. Hess cycle for combustion only

46. A system that can exchange energy but not matter with its surroundings is called

A. an open system B. a closed system C. an isolated system D. an adiabatic system only E. a homogeneous system

47. For the reaction N2 + 3H2 giving 2NH3, increasing the pressure shifts the equilibrium

A. to the left B. to the right C. not at all D. first left then right E. towards the gas with higher molar mass

48. A catalyst added to a reversible reaction at equilibrium

A. shifts the equilibrium to the right B. shifts the equilibrium to the left C. increases the value of Kc D. does not change the position of equilibrium E. reduces the yield

49. The pH of a 0.001 mol dm-3 solution of hydrochloric acid is

A. 1 B. 2 C. 3 D. 4 E. 11

50. At 25 degrees Celsius, the sum of pH and pOH for an aqueous solution is

A. 7 B. 10 C. 14 D. 1

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