🧪 CHEMISTRY MOCK EXAM (Grade 9–10) Topics Covered: Atoms & Molecules · Atomic Structure · Metals & Non-Metals · Bonding · Gases & Gas Tests · Types

SECTION A — Atoms, Molecules & Compounds

1. Water is considered a compound because it:
A. Exists naturally
B. Contains hydrogen and oxygen physically mixed
C. Contains hydrogen and oxygen chemically bonded
D. Is a liquid at room temperature

2. Oxygen used in hospitals is best described as:
A. A compound
B. A mixture
C. A molecule of an element
D. A single atom

3. Which substance contains only one type of atom?
A. Carbon dioxide
B. Sodium chloride
C. Iron
D. Water

4. Air is not a compound because it:
A. Has gases in it
B. Is colourless
C. Is a physical mixture
D. Has no fixed volume

SECTION B — Atomic Structure (Including Diagrams)

5. An atom is electrically neutral because:
A. Neutrons cancel electrons
B. Protons have no charge
C. Number of protons equals number of electrons
D. Electrons are uncharged

6. The atomic number of an element represents the number of:
A. Neutrons
B. Electrons + neutrons
C. Protons
D. Shells

7. Isotopes of the same element show similar chemical behavior because they have the same:
A. Mass number
B. Number of neutrons
C. Number of electrons
D. Atomic size

8. An atom loses one electron. What does it become?
A. A negative ion
B. A positive ion
C. An isotope
D. A neutron

9. Diagram description: An atom shows 2 electrons in the first shell and 6 in the second shell.
Which element is shown?
A. Carbon
B. Nitrogen
C. Oxygen
D. Neon

10. Diagram description: An atom has 11 protons, 12 neutrons, and 11 electrons.
Which statement is correct?
A. It is negatively charged
B. It is a sodium ion
C. It is neutral
D. It is magnesium

SECTION C — Metals & Non-Metals

11. Aluminium is used to make aircraft because it is:
A. Magnetic
B. Heavy
C. Strong and lightweight—-Answer
D. Brittle

12. Copper is used for electrical wiring mainly because it:
A. Is cheap
B. Has a low melting point
C. Conducts electricity well—-Answer
D. Is shiny

13. Which non-metal is commonly used to disinfect drinking water?
A. Oxygen
B. Nitrogen
C. Chlorine—Answer
D. Carbon

14. Metals conduct electricity because they have:
A. Fixed electrons
B. Delocalized electrons—answer
C. High density
D. Ionic bonds

15. Diagram description: A lattice of metal ions surrounded by a “sea of electrons” is shown.
Which property does this explain?
A. Brittleness
B. Electrical conductivity—-answer
C. Low melting point
D. Insolubility

SECTION D — Chemical Bonding

16. Sodium chloride forms because:
A. Sodium and chlorine share electrons
B. Sodium gains electrons
C. Sodium transfers electrons to chlorine—-answer
D. Chlorine transfers electrons to sodium

17. Sugar dissolves in water but does not conduct electricity because it is:
A. Ionic
B. Metallic
C. Covalent
D. An electrolyte—answer

18. Which compound is most likely to have a low melting point?
A. NaCl
B. MgO
C. CO₂——answer
D. CaCl₂

19. Covalent bonds usually form between:
A. Metals only
B. Metals and non-metals
C. Non-metals—-answer
D. Ions

20. Diagram description: Two non-metal atoms share two pairs of electrons.
This represents:
A. A single covalent bond——answer
B. A double covalent bond
C. An ionic bond
D. A metallic bond

SECTION E — Gases & Gas Tests

21. Gas particles differ from solid particles because they:
A. Vibrate only
B. Are closely packed
C. Move freely and randomly—-answer
D. Have fixed positions

22. Increasing the temperature of a gas causes particles to:
A. Move slower
B. Move faster—answer
C. Stop moving
D. Become heavier

23. A glowing splint relights in a gas jar. The gas is:
A. Hydrogen
B. Oxygen——answer
C. Carbon dioxide
D. Nitrogen

24. A gas turns limewater milky. This gas is:
A. Oxygen
B. Hydrogen
C. Carbon dioxide
D. Chlorine—-answer

25. A lighted splint makes a “pop” sound when placed in a gas. The gas is:
A. Oxygen
B. Carbon dioxide
C. Hydrogen—answer
D. Air

26. Diagram description: A gas is collected by downward displacement of air.
Which gas is most suitable?
A. Hydrogen
B. Oxygen
C. Carbon dioxide
D. Helium—answer

SECTION F — Types of Reactions

27. Rusting of iron is an example of:
A. Decomposition
B. Neutralization
C. Oxidation—-answer
D. Precipitation

28. Burning natural gas in a stove is a:
A. Decomposition reaction
B. Neutralization reaction
C. Combustion reaction—-answer
D. Displacement reaction

29. Acid reacting with a base in antacid tablets is an example of:
A. Oxidation
B. Neutralization—-answer
C. Combination
D. Decomposition

30. Diagram description: Zinc added to copper sulfate solution forms copper metal.
This is a:
A. Combination reaction
B. Decomposition reaction
C. Displacement reaction—-answer
D. Precipitation reaction

SECTION G — Rates of Reaction

31. Food spoils faster in warm weather because:
A. Reactions slow down
B. Reaction rate increases—-answer
C. Enzymes stop working
D. Temperature has no effect

32. Powdered solids react faster than large chunks because they have:
A. More mass
B. Higher density
C. Larger surface area—answer
D. Higher temperature

33. A catalyst increases reaction rate by:
A. Increasing temperature
B. Being used up
C. Lowering activation energy—-answer
D. Changing products

34. Graph description: Curve A is steeper than Curve B on a volume-time graph.
What condition most likely caused Curve A?
A. Lower temperature
B. Lower concentration
C. Higher concentration
D. Smaller surface area

SECTION H — Redox Reactions

35. Oxidation is defined as:
A. Gain of electrons
B. Loss of electrons—-answer
C. Gain of neutrons
D. Loss of protons

36. Reduction always involves:
A. Loss of electrons
B. Gain of electrons—answer
C. Gain of oxygen
D. Loss of neutrons

37. Which everyday device works due to redox reactions?
A. Plastic bottle
B. Battery—-answer
C. Glass cup
D. Wooden chair

38. Diagram description: Electrons move from zinc to copper ions.
Which statement is correct?
A. Zinc is reduced
B. Zinc is oxidized—-answer
C. Copper is oxidized
D. No redox occurs

SECTION I — Electrochemistry

39. A battery produces electrical energy because of:
A. Combustion
B. Redox reactions——Ans
C. Neutralization
D. Precipitation

40. Electroplating is mainly used to:
A. Increase mass
B. Prevent corrosion—ans
C. Reduce conductivity
D. Increase melting point

41. Electrolysis requires a substance that:
A. Is solid
B. Is an insulator
C. Conducts electricity—-ans
D. Is dry

42. Coating iron with zinc is called:
A. Electrolysis
B. Galvanization—ans
C. Rusting
D. Combustion

SECTION J — Stoichiometry (Real-Life Focus)

43. Balancing chemical equations is important to:
A. Increase reaction speed
B. Conserve mass—ans
C. Reduce temperature
D. Change products

44. If one reactant runs out first in a reaction, it is called the:
A. Excess reactant
B. Catalyst
C. Limiting reactant—ans
D. Product

45. The mole concept helps chemists to:
A. Measure heat
B. Count particles indirectly—-ans
C. Increase reaction rate
D. Test gases

46. In manufacturing, the limiting reactant determines the:
A. Colour of product
B. Maximum yield—-ans
C. Reaction speed
D. Temperature change

If you want next, I can:

• Mark this like a real exam

• Split it into Paper 1 / Paper 2

• Add calculation-based stoichiometry MCQs

• Or make an IGCSE / GCSE-style version

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A. Basics of Bonding

1. Why do atoms form chemical bonds?
A. To increase mass
B. To become electrically charged
C. To achieve a stable electron arrangement—-A
D. To increase temperature

2. Which of the following elements is most likely to form ionic bonds?
A. Carbon
B. Oxygen
C. Sodium—-A
D. Nitrogen

3. Which particle is transferred during ionic bonding?
A. Protons
B. Neutrons
C. Electrons—-A
D. Atoms

4. Which type of bond forms between two non-metal atoms?
A. Ionic
B. Covalent—-A
C. Metallic
D. Electrostatic

B. Ionic Bonding (Real-Life + Structure)

5. Sodium chloride dissolves in water and conducts electricity. This is because:
A. It forms molecules in water
B. It remains solid in water
C. It forms mobile ions in solution—-A
D. It releases electrons

6. Why do ionic compounds have high melting points?
A. Weak forces between molecules
B. Strong electrostatic forces between ions—-A
C. Low density of particles
D. Presence of free electrons

7. Which compound is most likely to be ionic?
A. CO₂
B. NH₃
C. NaCl——-A
D. CH₄

8. Which property is typical of ionic compounds?
A. Low melting point
B. Conduct electricity when solid
C. Conduct electricity when molten——A
D. Insoluble in water

C. Covalent Bonding

9. In a covalent bond, electrons are:
A. Transferred
B. Lost
C. Shared—-A
D. Gained permanently

10. Which substance contains only covalent bonds?
A. Sodium chloride
B. Magnesium oxide
C. Carbon dioxide——A
D. Calcium chloride

11. Why do simple covalent substances have low melting points?
A. Strong bonds between molecules
B. Weak forces between molecules——A
C. Strong ionic bonds
D. High number of ions

12. Which molecule contains a double covalent bond?
A. H₂
B. O₂
C. HCl
D. NH₃——A

D. Dot-and-Cross / Diagram-Based

13. A dot-and-cross diagram shows one pair of electrons shared between two atoms.
What type of bond is shown?
A. Ionic bond
B. Single covalent bond——A
C. Double covalent bond
D. Metallic bond

14. A diagram shows two atoms sharing two pairs of electrons.
This indicates:
A. Single bond
B. Double bond—-A
C. Ionic bond
D. Hydrogen bond

15. A diagram shows electrons transferred from magnesium to oxygen.
What ions are formed?
A. Mg⁺ and O⁻——A
B. Mg²⁺ and O²⁻
C. Mg⁻ and O⁺
D. Mg²⁻ and O²⁺

E. Metallic Bonding

16. Which diagram feature represents metallic bonding?
A. Shared electron pairs
B. Alternating positive and negative ions
C. Positive ions in a sea of delocalized electrons——A
D. Molecules held by weak forces

17. Which property of metals is explained by metallic bonding?
A. Low boiling point
B. Electrical conductivity—-A
C. Solubility in water
D. Brittleness

18. Metals are malleable because:
A. Ions can move past each other without breaking bonds—-A
B. Electrons are fixed in place
C. Metallic bonds are weak
D. Metals contain molecules

F. Bonding & Physical Properties (Application)

19. Which substance is most likely to be soft and have a low boiling point?
A. NaCl
B. MgO
C. CO₂——A
D. CaO

20. Which substance will NOT conduct electricity in any state?
A. Molten NaCl
B. Solid NaCl
C. Aqueous NaCl
D. Solid sugar—-A

21. Why does graphite conduct electricity even though it is covalent?
A. It contains ions
B. It has free-moving electrons——A
C. It is ionic
D. It dissolves in water

22. Diamond is very hard because:
A. It has weak forces between molecules
B. It has a giant covalent structure—-A
C. It is ionic
D. It contains free electrons

G. Exam-Style Thinking

23. Which pair of substances both have covalent bonding?
A. NaCl and MgO
B. CO₂ and H₂O—-A
C. CaCl₂ and NH₃
D. KBr and O₂

24. A compound has a high melting point and conducts electricity when molten.
Which type of bonding does it most likely have?
A. Covalent
B. Metallic
C. Ionic—-A
D. Hydrogen

25. Which change would increase the strength of an ionic bond?
A. Increasing ion charge
B. Increasing molecular mass
C. Decreasing number of ions
D. Removing electrons—-A