51. The most reactive noble gas is:

a) Neon
b) Argon
c) Krypton
d) Xenon
Answer: d) Xenon

52. Which of the following halogens is the most electronegative?

a) Chlorine
b) Bromine
c) Iodine
d) Fluorine
Answer: d) Fluorine

53. The noble gas used in gas discharge tubes is:

a) Radon
b) Helium
c) Neon
d) Argon
Answer: c) Neon

54. Which halogen is used in the synthesis of pharmaceuticals and disinfectants?

a) Fluorine
b) Chlorine
c) Bromine
d) Iodine
Answer: d) Iodine

55. The most common use of chlorine in industrial processes is:

a) Insecticides
b) Water purification
c) Food preservation
d) Synthetic fibers
Answer: b) Water purification

56. The noble gas used in low-temperature applications, such as superconductors, is:

a) Argon
b) Krypton
c) Neon
d) Xenon
Answer: b) Krypton

57. The chemical property that distinguishes noble gases from other elements is:

a) Their ability to form compounds
b) Their tendency to gain electrons
c) Their fully filled electron shells
d) Their high reactivity
Answer: c) Their fully filled electron shells

58. Which halogen is used in the treatment of water to remove organic impurities?

a) Fluorine
b) Chlorine
c) Bromine
d) Iodine
Answer: b) Chlorine

59. The trend of electron affinity in the halogens as you move down the group is:

a) Increases
b) Decreases
c) Remains constant
d) First increases and then decreases
Answer: b) Decreases

60. The noble gas used in electron tubes and fluorescent lamps is:

a) Helium
b) Neon
c) Argon
d) Xenon
Answer: b) Neon