In atomic physics, who is credited with the experimental discovery of the electron as a negatively charged subatomic particle?

Introduction / Context:

The discovery of the electron was a turning point in physics and chemistry because it proved that atoms are not indivisible. This question tests whether you know which scientist is credited with this discovery. It appears frequently in school level science and competitive exams under basic atomic structure and history of atomic models.

Given Data / Assumptions:

• The particle in question is the electron, a negatively charged subatomic particle.
• The question asks who discovered it experimentally.
• The options list several physicists who worked on atomic structure and radiation.
• You are expected to match each scientist to his main discovery and choose the correct one for the electron.

Concept / Approach:

J. J. Thomson, a British physicist, discovered the electron in 1897 using cathode ray tube experiments. By measuring the deflection of cathode rays in electric and magnetic fields, he concluded that these rays consist of tiny negatively charged particles, which he called corpuscles and which we now call electrons. This showed that atoms have smaller components. Other scientists in the options made important contributions, but to different aspects of atomic physics. Ernest Rutherford discovered the nucleus, James Chadwick discovered the neutron, and Niels Bohr proposed a quantum model for electron orbits. E. Goldstein studied canal rays, which led to insights about positive ions, not electrons.

Step-by-Step Solution:

Verification / Alternative check:

Textbooks on atomic structure commonly present a sequence: Thomson discovered electrons, Rutherford discovered the nucleus, Bohr refined the atomic model with energy levels and Chadwick discovered the neutron. This standard narrative appears in many educational resources. It clearly fixes the electron discovery to J. J. Thomson, providing strong confirmation for the answer.

Why Other Options Are Wrong:

E. Goldstein is known for discovering canal rays, which are streams of positive ions, not electrons.

Ernest Rutherford discovered the atomic nucleus through his alpha particle scattering experiments, not the electron.

James Chadwick discovered the neutron, a neutral particle in the nucleus, rather than the negatively charged electron.

Niels Bohr developed a model of the atom with quantised electron orbits but did not first identify the electron as a particle.

Common Pitfalls:

Because several famous physicists worked on atomic structure, students sometimes confuse who discovered what. A simple way to remember is to link each name with one key result: Thomson with electron, Rutherford with nucleus, Chadwick with neutron and Bohr with atomic model. Keeping these associations clear avoids mistakes when questions mix up their names in multiple choice options.

Final Answer:

The electron was discovered by J. J. Thomson.