Who proposed the ‘plum pudding’ theory of the divisible atom in which negatively charged electrons were scattered in a lump of positive charge like a raisin in plum pudding?

Sir JJ Thomson

The correct answer is option 3. Sir JJ Thomson.

The plum pudding model of the atom, proposed by Sir J.J. Thomson in 1904, suggested that atoms are composed of a diffuse cloud of positive charge with negatively charged electrons embedded within it, much like raisins in a plum pudding.

Thomson developed this model based on his experiments with cathode rays, which were streams of electrons observed in vacuum tubes. He discovered that these rays were composed of negatively charged particles, which he called electrons.

Thomson proposed that the negative charge of the electrons was balanced by the positive charge of the rest of the atom, distributed evenly throughout its volume. In this model, the electrons were thought to be randomly dispersed within the positively charged sphere, similar to the raisins in a plum pudding dessert.

However, this model was later replaced by Ernest Rutherford's nuclear model of the atom, which proposed that the positive charge of the atom is concentrated in a dense nucleus at its center, with electrons orbiting around it. Rutherford's experiments with alpha particles led to the discovery of the atomic nucleus and the development of the modern understanding of atomic structure.