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Quiz Chapter 2: Matter and Atomic Structure

10 questions ยท Form 4 Chemistry Bab 2: Matter and Atomic Structure

Question 1 of 10Score: 0

Why does temperature remain constant during the melting point plateau on a heating curve?

Full Question List & Answer Key

Prefer reading to quizzing? All 10 questions are listed below with the answer and explanation under each one.

1. Why does temperature remain constant during the melting point plateau on a heating curve?

  1. Heat energy is being destroyed by chemical bonds
  2. Heat energy absorbed is used to overcome forces of attraction between particles
  3. Particles lose kinetic energy to the surroundings
  4. The movement of particles stops completely
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Answer: B

During melting, absorbed heat energy breaks intermolecular attraction forces rather than increasing kinetic energy, keeping temperature constant.

2. Which scientist discovered the neutron in the atomic nucleus?

  1. J.J. Thomson
  2. Ernest Rutherford
  3. James Chadwick
  4. Niels Bohr
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Answer: C

James Chadwick discovered the neutron in 1932, showing it is a neutral subatomic particle located in the nucleus.

3. Which state of matter features particles that vibrate and rotate about fixed, locked positions?

  1. Solid
  2. Liquid
  3. Gas
  4. Plasma
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Answer: A

In solids, particles are closely packed in fixed orderly lattices, restricting movement to vibration and rotation on fixed points.

4. An atom of element Y has 17 protons and 18 neutrons. What is its standard atomic notation?

  1. 35 over 17 Y
  2. 18 over 17 Y
  3. 17 over 35 Y
  4. 35 over 18 Y
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Answer: A

Nucleon number A = 17 + 18 = 35. Proton number Z = 17. The notation is written with A as superscript and Z as subscript to the left of Y.

5. What happens to the kinetic energy of liquid particles when a liquid is cooled down to its freezing point?

  1. Kinetic energy increases
  2. Kinetic energy decreases
  3. Kinetic energy remains infinitely maximum
  4. Kinetic energy converts directly into light
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Answer: B

Cooling reduces temperature, which directly lowers the average kinetic energy of the particles.

6. What radioisotope is commonly applied to track underground pipe leaks in industrial operations?

  1. Sodium-24
  2. Cobalt-60
  3. Americium-241
  4. Uranium-238
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Answer: A

Sodium-24 is a short-lived radioactive tracer injected into pipes to locate underground leaks.

7. Which radioisotope is widely used in medical therapy to destroy cancer cells?

  1. Phosphorus-32
  2. Sodium-24
  3. Cobalt-60
  4. Americium-241
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Answer: C

Cobalt-60 emits gamma rays used in radiotherapy to destroy cancerous cells.

8. What is the physical process name when a gas converts directly into a solid without becoming a liquid?

  1. Sublimation
  2. Condensation
  3. Evaporation
  4. Deposition
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Answer: D

Deposition is the direct phase change from gas to solid.

9. What is defined as the total number of protons and neutrons in an atomic nucleus?

  1. Proton number
  2. Isotope index
  3. Electron configuration
  4. Nucleon number
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Answer: D

Nucleon number (mass number) is the sum of protons and neutrons present in an atom's nucleus.

10. If an atom has a proton number of 11 and a nucleon number of 23, how many neutrons does it contain?

  1. 11
  2. 12
  3. 23
  4. 34
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Answer: B

Number of neutrons = Nucleon number - Proton number = 23 - 11 = 12.

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