With reference to the discovery of sub-atomic particles, consider the following statements: 1. The presence of charged particles in an atom was revealed by the study of static electricity and conduction conditions. 2. E. Goldstein discovered the electron before the identification of canal rays. 3. Canal rays are negatively charged radiations. Which of the statements given above is/are correct?

Correct Option The correct option is (a). Explanation The structure of the atom was elucidated through a series of experiments in the late 19th and early 20th centuries. These experiments, particularly those involving electrical discharge through gases, established that atoms are divisible and composed of charged sub-atomic particles. Statement-wise Analysis - Statement 1 is Correct: The initial indication that atoms might contain charged particles came from the study of static electricity and the conditions under which electricity is conducted by different substances. These observations suggested that matter possesses an electrical nature. - Statement 2 is Incorrect: E. Goldstein did not discover the electron. In 1886, E. Goldstein discovered new radiations in a gas discharge and named them canal rays. The electron was discovered later by J.J. Thomson in 1897 using cathode ray tube experiments. - Statement 3 is Incorrect: Canal rays are positively charged radiations, not negatively charged. These rays consist of positively charged ions created when gas atoms lose electrons in a discharge tube. In contrast, cathode rays are negatively charged. Key Takeaway Canal rays (anode rays) are positively charged radiations discovered by E. Goldstein, whereas electrons are negatively charged constituents of cathode rays discovered by J.J. Thomson.

NCERT Class 9 Science — Chapter 4: Structure of the atom

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With reference to the discovery of sub-atomic particles, consider the following statements:

The presence of charged particles in an atom was revealed by the study of static electricity and conduction conditions.
E. Goldstein discovered the electron before the identification of canal rays.
Canal rays are negatively charged radiations.

Which of the statements given above is/are correct?

Official previous-year question

Verified 1 Aug 2026.

Options

A1 only
B2 only
C1 and 3 only
D1, 2 and 3

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Solution

Correct Option

The correct option is (a).

Explanation

The structure of the atom was elucidated through a series of experiments in the late 19th and early 20th centuries. These experiments, particularly those involving electrical discharge through gases, established that atoms are divisible and composed of charged sub-atomic particles.

Statement-wise Analysis

Statement 1 is Correct: The initial indication that atoms might contain charged particles came from the study of static electricity and the conditions under which electricity is conducted by different substances. These observations suggested that matter possesses an electrical nature.
Statement 2 is Incorrect: E. Goldstein did not discover the electron. In 1886, E. Goldstein discovered new radiations in a gas discharge and named them canal rays. The electron was discovered later by J.J. Thomson in 1897 using cathode ray tube experiments.
Statement 3 is Incorrect: Canal rays are positively charged radiations, not negatively charged. These rays consist of positively charged ions created when gas atoms lose electrons in a discharge tube. In contrast, cathode rays are negatively charged.

Key Takeaway

Canal rays (anode rays) are positively charged radiations discovered by E. Goldstein, whereas electrons are negatively charged constituents of cathode rays discovered by J.J. Thomson.

Your note

More from Chapter 4: Structure of the atom

Which sub-atomic particle was identified by J. Chadwick in 1932?

easy

With reference to Neils Bohr’s model of the atom, consider the following statements: 1. Only certain special orbits known as discrete orbits of electrons are allowed inside the atom. 2. Electrons radiate energy continuously while revolving in discrete orbits. 3. These discrete orbits are called energy levels. Which of the statements given above is/are correct?

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Consider the following statements regarding the discovery and properties of neutrons: 1. They were discovered by J.J. Thomson in 1897. 2. They are present in the nucleus of all atoms including hydrogen. 3. A neutron has no charge and a mass nearly equal to that of a proton. Which of the statements given above is/are correct?

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With reference to 'Valency', consider the following statements: 1. It is the combining capacity of the atoms of elements. 2. Atoms react to achieve a duplet in the outermost shell in all cases. 3. If the outermost shell has 8 electrons, the valency is 8. Which of the statements given above is/are correct?

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With reference to the definition of an element, consider the following statements: 1. Elements are defined by the number of protons they possess. 2. Atoms of a given element can have different numbers of protons. 3. The atomic number is characteristic of a particular element.

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Correct Option

The correct option is (a).

Explanation

Statement-wise Analysis

Statement 1 is Correct: The initial indication that atoms might contain charged particles came from the study of static electricity and the conditions under which electricity is conducted by different substances. These observations suggested that matter possesses an electrical nature.
Statement 2 is Incorrect: E. Goldstein did not discover the electron. In 1886, E. Goldstein discovered new radiations in a gas discharge and named them canal rays. The electron was discovered later by J.J. Thomson in 1897 using cathode ray tube experiments.
Statement 3 is Incorrect: Canal rays are positively charged radiations, not negatively charged. These rays consist of positively charged ions created when gas atoms lose electrons in a discharge tube. In contrast, cathode rays are negatively charged.

Key Takeaway

Canal rays (anode rays) are positively charged radiations discovered by E. Goldstein, whereas electrons are negatively charged constituents of cathode rays discovered by J.J. Thomson.