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Structure Of The Atom- 1 - Free MCQ Practice Test with solutions, UPSC


MCQ Practice Test & Solutions: Test: Structure Of The Atom- 1 (10 Questions)

You can prepare effectively for UPSC Science & Technology for UPSC CSE with this dedicated MCQ Practice Test (available with solutions) on the important topic of "Test: Structure Of The Atom- 1". These 10 questions have been designed by the experts with the latest curriculum of UPSC 2026, to help you master the concept.

Test Highlights:

  • - Format: Multiple Choice Questions (MCQ)
  • - Duration: 10 minutes
  • - Number of Questions: 10

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Test: Structure Of The Atom- 1 - Question 1
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Which scientist discovered the electron?

Detailed Solution: Question 1

Answer: a) J.J. Thomson

Test: Structure Of The Atom- 1 - Question 2
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To determine which figure correctly represents a Magnesium (Mg) atom, we need to identify the one with the appropriate number of neutrons (n) and protons (p).

Detailed Solution: Question 2

The Magnesium atom with 12 protons (p) and 12 neutrons (n) is represented by option D. This is derived from the atomic number (12 protons) and the mass number of Mg-24 (12 neutrons).

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Test: Structure Of The Atom- 1 - Question 3
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When alpha-particles are sent through a thin metal foil, most of them pass through easily because _______.

Detailed Solution: Question 3

When alpha particles are sent through a thin metal foil, most of them pass through easily because most of the atom is empty space. According to Rutherford's model of the atom, the majority of an atom consists of empty space with the nucleus occupying a very small volume. This allows alpha particles to traverse the foil without significant obstruction, as there is minimal material to interact with along their path.

Test: Structure Of The Atom- 1 - Question 4
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According to Bohr’s model, which of the following is true about electron orbits?

Detailed Solution: Question 4

Neils Bohr proposed that electrons revolve around the nucleus only in specific allowed orbits called discrete orbits or energy levels.

Test: Structure Of The Atom- 1 - Question 5
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Which of the following subatomic particles have no charge?

Detailed Solution: Question 5

The subatomic particle with no charge is the neutron. Neutrons are one of the components of an atom's nucleus.

  • Neutrons have no electric charge.
  • They are found in the nucleus alongside protons, which have a positive charge.
  • Electrons, which orbit the nucleus, have a negative charge.

Test: Structure Of The Atom- 1 - Question 6
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Rutherford’s α-particle scattering experiment demonstrated which of the following? (i) Electrons have negative charge. (ii) The mass and positive charge of an atom are concentrated in a small nucleus. (iii) Neutrons exist in the nucleus. (iv) Most of the space in an atom is empty. Which of the above statements are correct?

Detailed Solution: Question 6

Statements (ii) and (iv) are correct. Rutherford's experiment showed that atoms have a small, dense nucleus containing most of the atom's mass and positive charge. Additionally, it revealed that most of the atom is empty space since alpha particles mostly passed through the foil unhindered. - Statement (i) was established by J.J. Thomson during his cathode ray experiments. - Statement (iii), the existence of neutrons, was discovered later by James Chadwick and was not part of Rutherford's findings.

Test: Structure Of The Atom- 1 - Question 7
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The atomic number of an element is equal to:

Detailed Solution: Question 7

The atomic number of an element is defined by: The number of protons in its nucleus. This number is crucial because: It determines the element's identity. It is equal to the number of electrons in a neutral atom.

Test: Structure Of The Atom- 1 - Question 8
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Isotopes are atoms of the same element which have:

Detailed Solution: Question 8

- Isotopes Definition: Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons.
- Atomic Number: This is the number of protons in an atom's nucleus, which defines the element.
- Mass Number: This is the total number of protons and neutrons in an atom's nucleus.
- Choice B describes isotopes accurately: they have different mass numbers due to varying neutrons, while their atomic number (protons) remains the same.

Test: Structure Of The Atom- 1 - Question 9
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Isobars are atoms that have:

Detailed Solution: Question 9

Isobars are defined by their mass numbers and atomic numbers.

  • Mass Numbers: Isobars have the same mass number.
  • Atomic Numbers: They possess different atomic numbers.

This means isobars are atoms with the same total number of protons and neutrons combined but differ in their number of protons (atomic number).

Test: Structure Of The Atom- 1 - Question 10
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Which law states that "In a chemical substance, the elements are always present in definite proportions by mass"?

Detailed Solution: Question 10

The Law of Definite Proportions is a fundamental principle in chemistry.

  • It states that in a chemical substance, the elements are always combined in the same proportions by mass.
  • This means the ratio of the masses of the elements in a compound is constant, no matter the source or amount of the compound.

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This test contains 10 MCQs on Structure Of The Atom- 1 with detailed solutions for each question. It is part of the Science & Technology for UPSC CSE course on EduRev, designed to align with the current UPSC syllabus. Each solution explains not just the correct answer but also gives you an understanding of the topic — not just to attempt the question but also help you prepare for the exam with practice.

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