100 Likely JAMB Chemistry Questions and Answers for 2026

---

Atomic Structure & Periodic Table (1–15)

1. The atomic number of an element represents the number of:
   Answer: Protons

2. Atomic mass is the sum of:
   Answer: Protons and neutrons

3. Electrons revolve around the nucleus while protons and neutrons:
   Answer: Remain inside the nucleus

4. Which of the following metals is the most reactive?
   A. Sodium B. Potassium C. Francium D. Lithium
   Answer: C. Francium

5. Which is the hardest natural substance?
   Answer: Diamond

6. The lowest oxidation state of iron is:
   Answer: 0

7. Elements in the same group of the periodic table are called:
   Answer: Congeners

8. Fourth and fifth periods of the periodic table contain how many elements each?
   Answer: 18

9. Fluorine is classified as:
   Answer: The most reactive non-metal

10. Dmitri Mendeleev is famous for:
    Answer: Developing the periodic table

11. Which element is radioactive?
    Answer: Uranium

12. Atomic number is also equal to the number of:
    Answer: Electrons in a neutral atom

13. Which of these is a noble gas?
    A. Nitrogen B. Argon C. Oxygen D. Fluorine
    Answer: B. Argon

14. Which element is an alkali metal?
    A. Sodium B. Magnesium C. Aluminum D. Chlorine
    Answer: A. Sodium

15. The tendency of atoms to gain electrons is called:
    Answer: Electronegativity

---

Chemical Reactions & Compounds (16–30)

16. Burning kerosene produces:
    Answer: CO₂ + H₂O

17. All nitrates are:
    Answer: Soluble in water

18. Most nitrates decompose when:
    Answer: Heated

19. Hydrogen gas is the lightest gas. True or False?
    Answer: True

20. Metals form ions by:
    Answer: Losing electrons

21. An oxide that forms an acid in water is called:
    Answer: Acid anhydride

22. Thermite process is used for:
    Answer: Welding broken metal parts

23. Bessemer process is used to produce:
    Answer: Steel

24. NaOH is used in:
    Answer: Soap production

25. Oxygen is the most abundant element in:
    Answer: Earth’s crust

26. Methane is called fire damp because it:
    Answer: Causes explosions in coal mines

27. Aliphatic compounds have:
    Answer: Open carbon chains

28. Aromatic compounds contain:
    Answer: Benzene rings

29. Amines have a characteristic:
    Answer: Fishy smell

30. Nigerian crude oil is called sweet crude due to:
    Answer: Low sulphur content

---

Organic Chemistry (31–45)

31. The ability of carbon to form long chains is:
    Answer: Catenation

32. Hydrocarbons are composed of:
    Answer: Carbon and hydrogen only

33. Hydrogenation of alkynes produces:
    Answer: Alkanes

34. Consecutive members of the alkane homologous series differ by:
    Answer: CH₂

35. Benzene is classified as:
    Answer: Aromatic hydrocarbon

36. Methane belongs to which hydrocarbon group?
    Answer: Alkane

37. Ethene belongs to which hydrocarbon group?
    Answer: Alkene

38. The process of converting alkenes to alkanes is called:
    Answer: Hydrogenation

39. Isomers have:
    Answer: Same molecular formula but different structures

40. Which functional group is present in alcohols?
    Answer: –OH

41. Esters are formed from:
    Answer: Alcohol + Carboxylic acid

42. Carboxylic acids react with bases to form:
    Answer: Salt + Water

43. Organic compounds containing nitrogen are called:
    Answer: Amines

44. Compounds with benzene rings are:
    Answer: Aromatic compounds

45. The simplest alkane is:
    Answer: Methane

---

Electrochemistry (46–55)

46. During electrolysis, reduction occurs at:
    Answer: Cathode

47. Oxidation occurs at:
    Answer: Anode

48. Cathode → Reduction, Anode → Oxidation. True or False?
    Answer: True

49. In Downs cell, sodium is produced from:
    Answer: Molten NaCl

50. Electrolyte in Downs cell is mixed with:
    Answer: CaCl₂

51. Electrolysis of water produces:
    Answer: Hydrogen and Oxygen

52. Faraday is known for:
    Answer: Laws of electrolysis

53. Electric current flows through:
    Answer: Electrolytes

54. Which electrode attracts cations?
    Answer: Cathode

55. Which electrode attracts anions?
    Answer: Anode

---

Physical Chemistry (56–65)

56. Pure substances have definite:
    Answer: Boiling and melting points

57. Viscosity is:
    Answer: Resistance to flow

58. Water boils when:
    Answer: Vapour pressure = Atmospheric pressure

59. Energy from the sun is produced by:
    Answer: Nuclear fusion

60. Nuclear energy can be obtained through:
    Answer: Fusion and fission

61. Optically active compounds:
    Answer: Rotate plane-polarised light

62. Cathode ray tubes were early:
    Answer: Television tubes

63. The charge of an electron is:
    Answer: −1.60 × 10⁻¹⁹ C

64. Gas laws relate pressure, volume, and:
    Answer: Temperature

65. Sublimation is:
    Answer: Solid → Gas

---

Radioactivity & Nuclear Chemistry (66–75)

66. Radioactivity is:
    Answer: Spontaneous disintegration of atomic nuclei

67. Alpha particles can be stopped by:
    Answer: Paper

68. Beta particles can be stopped by:
    Answer: Aluminium foil

69. Gamma rays are stopped by:
    Answer: Lead blocks

70. Alpha particles have the least penetrating power. True or False?
    Answer: True

71. Antoine Becquerel discovered:
    Answer: Radioactivity

72. Marie Curie named:
    Answer: Radioactivity

73. Ernest Rutherford is called:
    Answer: Father of nuclear science

74. Uranium undergoes:
    Answer: Radioactive decay

75. Polonium is:
    Answer: Radioactive element

---

Atmospheric & Environmental Chemistry (76–85)

76. The lithosphere is made of:
    Answer: Rocks and soil

77. Atmosphere contains:
    Answer: 78% N₂, 21% O₂, 1% other gases

78. Water vapour is a:
    Answer: Greenhouse gas

79. Ozone protects us from:
    Answer: UV radiation

80. Acid rain contains:
    Answer: H₂SO₄ + HNO₃

81. Fluorine is the most reactive:
    Answer: Non-metal

82. Carbon dioxide contributes to:
    Answer: Global warming

83. Industrial HNO₃ is produced via:
    Answer: Ostwald process

84. The most used industrial chemical is:
    Answer: H₂SO₄

85. Air is mainly composed of:
    Answer: Nitrogen

---

Metals & Industrial Chemistry (86–95)

86. The Bessemer process produces:
    Answer: Steel

87. Acheson process produces:
    Answer: Graphite

88. Sodium is obtained from:
    Answer: Electrolysis of molten NaCl

89. Thermite reaction involves:
    Answer: Aluminum + Metal oxide

90. Metals react with acids to produce:
    Answer: Salt + Hydrogen

91. CaCO₃ decomposes on heating to produce:
    Answer: CaO + CO₂

92. Iron rusts in presence of:
    Answer: Water and Oxygen

93. Alloy of copper and tin is called:
    Answer: Bronze

94. Galvanization protects iron by coating with:
    Answer: Zinc

95. Industrial ammonia is produced by:
    Answer: Haber process

---

Likely Trick Questions (96–100)

96. Which gas is used in welding torches?
    Answer: Acetylene

97. Fire damp in mines is:
    Answer: Methane

98. Which acid is used in car batteries?
    Answer: H₂SO₄

99. Which element has atomic number 8?
    Answer: Oxygen

100. Nuclear fission of uranium produces:
     Answer: Energy + Neutrons + Fission fragments