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Quiz Chapter 2: Matter and Atomic Structure

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

10 questions · plays in fullscreen

Full Question List & Answer Key

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

1. Who proposed the atomic model showing electrons moving in specific, designated shells around a positive nucleus?

  1. John Dalton
  2. Niels Bohr
  3. J.J. Thomson
  4. Ernest Rutherford
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Answer: B

Niels Bohr improved Rutherford's model by introducing fixed electron shells/energy levels surrounding the nucleus.

2. 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.

3. Chlorine exists as two natural isotopes: 75% 35Cl and 25% 37Cl. What is its relative atomic mass?

  1. 36.0
  2. 35.5
  3. 35.0
  4. 36.5
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Answer: B

Relative atomic mass = (75 × 35) + (25 × 37)100 = 2625 + 925100 = 35.5.

4. Which isotope is utilized by archaeologists to determine the age of ancient organic fossils?

  1. Uranium-235
  2. Iodine-131
  3. Carbon-14
  4. Phosphorus-32
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Answer: C

Carbon-14 radiocarbon dating measures the decay of carbon-14 in formerly living organic matter.

5. 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.

6. Which pair of atoms represents isotopes of the same element?

  1. Carbon-12 and Carbon-14
  2. Carbon-12 and Nitrogen-14
  3. Sodium-23 and Magnesium-24
  4. Oxygen-16 and Nitrogen-14
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Answer: A

Isotopes are atoms of the same element (same proton number = 6 for carbon) with different nucleon numbers (12 and 14).

7. Which subatomic particle has a relative charge of -1 and negligible relative mass?

  1. Proton
  2. Neutron
  3. Positron
  4. Electron
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Answer: D

An electron carries a charge of -1 and has a tiny relative mass of 11840.

8. 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.

9. 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.

10. 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.

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