J. j. thompson is credited with discovering the

He was credited with the discovery and identification of the electron, the first subatomic particle to be described.

Explanation:

Joseph John Thomson was an important English physicist, born on December 18, 1856 in Manchester, who discovered the electron.

The atomic model of Thomson was proposed in the year 1898 by the English physicist Joseph John Thomson or simply J.J. Thomson. After having several experimental evidences on the existence of the electron, it overturned the theory of the indivisibility of the atom proposed by John Dalton.

Thomson, from his model, confirmed and proved the existence of electrons (particles with negative electric charge) in the atom, that is, the atom has subatomic particles.

think its the third option