Who was the first one to propose a model for the structure of an atom?

Correct answer: (d) J. J. Thomson

Explanation

J. J. Thomson (1898) proposed the first atomic model – the Plum Pudding Model, with electrons embedded in a positively charged sphere.

Rutherford (1911) later gave the nuclear model and Niels Bohr (1913) the energy-level model.

E. Goldstein discovered the proton (canal rays) but did not propose an atomic structure.