Which of the following options represents sub-atomic particles found in Thomson's model of an atom?

Correct option is A

The correct answer is indeed (A) Only electrons.

Explanation:

   Thomson's Discovery:

• J.J. Thomson's experiments in 1897 led to the discovery of the electron, a negatively charged subatomic particle.
• He proposed the "plum pudding model", where electrons were embedded in a diffuse positive charge.

 Nature of Thomson's Model:

• Thomson's model did not specifically identify protons or neutrons because these particles had not yet been discovered at the time.
• The focus was solely on electrons and the idea of a positive charge acting as a balance to maintain electrical neutrality.

Why Other Options are Incorrect:

• Electrons and protons both: Protons were discovered later by Ernest Rutherford in 1917.
• Protons and neutrons both: Neutrons were discovered even later, in 1932, by James Chadwick.
• Only protons: This does not align with Thomson's model, as it emphasized electrons.