The next major subatomic particle discovered after the electron was the proton.

Discovery order: electron → proton → neutron

  • The electron was identified first by J. J. Thomson in 1897 using cathode ray tube experiments.
  • The next key subatomic particle to be recognized was the positively charged proton , emerging from work on canal rays and later clarified by Ernest Rutherford’s experiments in the early 1900s.
  • The electrically neutral neutron came later, discovered by James Chadwick in 1932.

Quick Scoop: why the proton counts as “next”

  • When people ask “which subatomic particle was discovered next after the electron?”, they usually mean the next one that became accepted as a fundamental constituent of the atom, not later‑found exotic particles.
  • In that historical sequence of basic atomic building blocks, the proton is regarded as the one discovered after the electron, with the neutron closing out the trio of familiar subatomic particles.

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