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Structure of Atom (9 Science)

The atom consists of a nucleus containing protons and neutrons, surrounded by electrons in various shells. Understanding atomic structure is fundamental to

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TL;DR: The atom consists of a nucleus containing protons and neutrons, surrounded by electrons in various shells. Understanding atomic structure is fundament…

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The atom consists of a nucleus containing protons and neutrons, surrounded by electrons in various shells. Understanding atomic structure is fundamental to

Structure of Atom MCQs with Answers & Explanations

Q1. Who proposed the nuclear model of the atom?

  1. J.J. Thomson
  2. Ernest Rutherford ✓ (correct)
  3. Niels Bohr
  4. Max Planck

Q2. The charge on an electron is:

  1. Positive
  2. Negative ✓ (correct)
  3. Neutral
  4. Can be either positive or negative

Q3. Which particles are present in the nucleus?

  1. Only protons
  2. Only electrons
  3. Protons and neutrons ✓ (correct)
  4. Protons and electrons

Q4. An atom has 8 protons and 8 neutrons. What is its mass number?

  1. 8
  2. 16 ✓ (correct)
  3. 4
  4. 24

Q5. Isotopes are atoms that have:

  1. Same protons but different neutrons ✓ (correct)
  2. Same electrons but different protons
  3. Same mass but different protons
  4. Different electrons and protons

Q6. Bohr's model explains the stability of atoms by:

  1. Electron orbits in fixed energy levels ✓ (correct)
  2. Nucleus repelling electrons
  3. Electrons moving randomly
  4. Electrons closer to nucleus are more stable

Q7. What is the maximum number of electrons in the second shell of an atom?

  1. 2
  2. 4
  3. 6
  4. 8 ✓ (correct)

Q8. The symbol X has atomic number 17 and mass number 35. How many neutrons does it have?

  1. 17
  2. 18 ✓ (correct)
  3. 35
  4. 52

Q9. Which of the following is a correct electron configuration for Oxygen (atomic number 8)?

  1. 2, 4
  2. 2, 6 ✓ (correct)
  3. 2, 8
  4. 4, 4

Q10. The nucleus accounts for most of the atom's:

  1. Volume
  2. Mass ✓ (correct)
  3. Charge
  4. Electrons

Frequently Asked Questions

What did Rutherford's gold foil experiment prove?

The experiment showed that most of the atom is empty space and the positive charge is concentrated in a small nucleus at the center, disproving Thomson's plum pudding model.

How do electrons gain energy to move to higher orbits in Bohr's model?

Electrons absorb specific amounts of energy (photons) equal to the energy difference between two orbits and jump to a higher energy level.

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