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.