1. Which of the following elements has the largest atomic radius?

 A) Oxygen

 B) Fluorine

 C) Sulfur

 D) Chlorine

 2. If a solution has a pH of 3, which of the following is true?

 A) The solution is basic.
 B) The solution is neutral.
 C) The solution is acidic.
 D) The solution has no charge.
3. What type of bond is most likely to form between a sodium (Na) atom and
a chlorine (Cl) atom?
 A) Covalent
 B) Ionic
 C) Hydrogen
 D) Metallic
4. Which of the following compounds is polar?
 A) Carbon dioxide
 B) Methane
 C) Water
 D) Benzene

5. What is the molecular geometry of methane (CH₄)?

  A) Linear
 B) Trigonal planar
 C) Tetrahedral
 D) Bent
6. Which law states that the volume of a gas is inversely proportional to its
pressure, given a constant temperature?
 A) Boyle's Law
 B) Charles's Law
 C) Avogadro's Law
 D) Ideal Gas Law
7. A sample of gas has a volume of 2 liters at a pressure of 1 atmosphere. If
the pressure increases to 2 atmospheres at constant temperature, what will
the new volume be?
 A) 0.5 liters
 B) 1 liter
 C) 2 liters
 D) 4 liters
8. What is the electron configuration of an oxygen atom?
 A) 1s² 2s² 2p⁴

 B) 1s² 2s² 2p⁶

 C) 1s² 2s¹ 2p⁶

 D) 1s² 2s² 2p³


9. Which of the following statements is true about catalysts?
 A) They increase the activation energy.
 B) They are consumed in the reaction.
 C) They decrease the activation energy.
 D) They change the products of a reaction.
10. When balancing chemical equations, which of the following is conserved?
 A) Mass only
 B) Atoms only
 C) Both mass and atoms
 D) Neither mass nor atoms
11. In an endothermic reaction, energy is:
 A) Released to the surroundings.
 B) Absorbed from the surroundings.
 C) Unchanged.
 D) Transformed into mass.
12. How many moles of NaCl are in 58.5 grams of NaCl (Molar mass of NaCl =
58.5 g/mol)?
 A) 0.5 moles
 B) 1 mole
 C) 2 moles
 D) 3 moles
13. Which of the following best explains why ice floats on water?
 A) Ice is denser than water.
 B) The molecules in ice are closer together.
 C) Ice forms a crystal structure that is less dense.
 D) Water has a lower specific heat than ice.
14. Which of these is an example of a chemical change?
 A) Melting of ice
 B) Shredding of paper
 C) Burning of wood
 D) Dissolving sugar in water
15. In the reaction 2H₂ + O₂ → 2H₂O, how many grams of H₂O are produced
 from 4 grams of H₂? (Molar mass of H₂ = 2 g/mol, H₂O = 18 g/mol)
 A) 18 grams
 B) 36 grams
 C) 9 grams
 D) 72 grams
16. Which of the following is NOT a property of metals?
 A) Malleability
 B) Ductility
 C) Brittleness
 D) Electrical conductivity
17. Which element has an atomic number of 12?
 A) Sodium
 B) Magnesium
 C) Aluminum
 D) Silicon
18. The element with the highest electronegativity is:
 A) Hydrogen
 B) Carbon
 C) Oxygen
 D) Fluorine
19. What is the shape of the carbon dioxide (CO₂) molecule?
 A) Bent

 B) Trigonal planar

 C) Tetrahedral

 D) Linear
20. If a 100 g sample of a radioactive isotope has a half-life of 5 years, how
much of the isotope will remain after 10 years?
 A) 100 g
 B) 50 g
 C) 25 g
 D) 12.5 g
21. What is the oxidation state of sulfur in
H2SO4\text{H}_2\text{SO}_4H2SO4?
 A) +2
 B) +4
 C) +6
 D) 0
22. Which of the following gases is most likely to behave ideally under
standard conditions?
 A) Oxygen
 B) Nitrogen
 C) Carbon dioxide
 D) Ammonia
23. The molar mass of C₂H₅OH (ethanol) is:
 A) 34 g/mol
 B) 44 g/mol
 C) 46 g/mol
 D) 58 g/mol
24. Which intermolecular force is strongest in hydrogen fluoride (HF)?
 A) Dipole-dipole
 B) London dispersion
 C) Hydrogen bonding
 D) Ionic bonding
25. What happens to the equilibrium position of a reaction if more reactant is
added to a system at equilibrium?
 A) Shifts to the right
 B) Shifts to the left
  C) No change
 D) Temperature decreases
26. If a substance changes from solid to gas without passing through the
liquid phase, this process is known as:
 A) Condensation
 B) Sublimation
 C) Deposition
 D) Freezing
27. Which of the following solutions has the highest concentration of solute?
 A) 1 M NaCl
 B) 0.5 M KBr
 C) 2 M KNO₃
 D) 0.1 M CaCl₂
28. What is the effect of increasing temperature on the rate of a chemical
reaction?
 A) Decreases the rate
 B) Increases the rate
 C) No effect
 D) Reverses the reaction
29. Which gas law is represented by the equation PV=nRTPV = nRTPV=nRT?
 A) Boyle’s Law

 B) Charles’s Law

 C) Ideal Gas Law

 D) Avogadro’s Law
30. When a redox reaction occurs, which of the following is true?
 A) Electrons are shared equally.

 B) Electrons are transferred.

 C) Electrons are destroyed.

 D) Electrons are created.
31. The specific heat capacity of a substance refers to:
 A) The temperature at which it melts.
 B) The amount of heat required to change its temperature by 1°C.
 C) Its thermal conductivity.
 D) Its density.
32. A solution with a [H⁺] concentration of 1×10−81 \times 10^{-8}1×10−8 M
has a pH of:
 A) 2
 B) 6
 C) 8
 D) 14
33. Which quantum number describes the shape of an atomic orbital?
 A) Principal quantum number (n)
 B) Angular momentum quantum number (l)
 C) Magnetic quantum number (m)
 D) Spin quantum number (s)
34. Which element has the electronic configuration of 1s22s22p63s23p51s^2
2s^2 2p^6 3s^2 3p^51s22s22p63s23p5?
 A) Argon
 B) Chlorine
 C) Potassium
 D) Sulfur
35. In the reaction N₂ + 3H₂ → 2NH₃, how many moles of NH₃ can be
produced from 6 moles of H₂?
 A) 1 mole
 B) 2 moles
 C) 3 moles
 D) 4 moles
36. Which of the following reactions is an example of a decomposition reaction?
 A) 2H₂ + O₂ → 2H₂O

 B) Mg + 2HCl → MgCl₂ + H₂

 C) CaCO₃ → CaO + CO₂

 D) NaCl + AgNO₃ → NaNO₃ + AgCl

37. How many atoms of hydrogen are present in 1 mole of H₂O?
 A) 6.02 × 10²³

 B) 1.20 × 10²⁴

 C) 1.80 × 10²⁴

 D) 3.01 × 10²³
38. Which is the strongest acid in aqueous solution?
 A) HCl

 B) HF

 C) H₂CO₃

 D) CH₃COOH

39. A sample contains 3.01 x 10²³ molecules of CO₂. How many moles of CO₂ does it
contain?
 A) 0.25 moles

 B) 0.5 moles

 C) 1 mole

 D) 2 moles
40. What is the most likely type of bonding in a compound formed between
lithium and fluorine?
 A) Covalent

 B) Ionic

 C) Metallic

 D) Hydrogen bonding
41. In a chemical equilibrium, what happens to the concentration of products
 if a catalyst is added?
 A) Increases
 B) Decreases
 C) Remains unchanged
 D) Concentration depends on temperature
42. Which of the following is an example of a heterogeneous mixture?
 A) Saltwater
 B) Vinegar
 C) Sugar water
 D) Salad dressing
43. What is the molarity of a solution containing 0.5 moles of NaCl in 0.25 L of
solution?
 A) 0.5 M

 B) 1 M

 C) 2 M

 D) 3 M
44. Which of the following statements about metals is true?
 A) Metals are brittle.

 B) Metals are generally good conductors of electricity.

 C) Metals are non-reactive.

 D) Metals have low melting points.

45. What is the oxidation state of nitrogen in NH₄⁺?
 A) -3

 B) -1

 C) +1

 D) +3
46. The atomic mass of chlorine is approximately 35.5 amu. This is because:
 A) Chlorine is a mixture of isotopes.
 B) Chlorine atoms have varying masses.
 C) Chlorine contains protons and neutrons.
 D) Chlorine has a high atomic number.
47. Which of the following is true for an exothermic reaction?
 A) ΔH > 0
 B) Energy is absorbed from surroundings.
 C) ΔH < 0
 D) The products have more energy than reactants.
48. The balanced chemical equation for the combustion of methane is:
 A) CH₄ + O₂ → CO + H₂O
 B) CH₄ + 2O₂ → CO₂ + 2H₂O
 C) CH₄ + O₂ → CO₂ + H₂O
 D) 2CH₄ + 2O₂ → 2CO₂ + H₂
49. What is the main factor that determines the boiling point of a substance?
 A) Density
 B) Molecular weight
 C) Intermolecular forces
 D) Solubility
50. Which of the following best describes isotopes?
 A) Atoms with different numbers of protons.
 B) Atoms with different atomic numbers.
 C) Atoms of the same element with different numbers of neutrons.
 D) Atoms of different elements with the same mass number.