Final answer:
J. J. Thomson created the "plum pudding model" of the atom in 1904, imagining the atom as a sphere filled with a jelly-like positive charge and embedded with electrons, similar to a dessert with plums.
Step-by-step explanation:
The "plum pudding model" of the atom was created by J. J. Thomson in 1904. This conceptual model described the atom as a sphere of positive charge with embedded electrons, much like plums in a pudding or blueberries in a muffin. Thomson's model stemmed from his discovery of the electron and suggested a jelly-like or soup-like positive matrix in which electrons were somewhat mobile.
This model was eventually replaced by Ernest Rutherford's nuclear model after his gold foil experiment suggested a more complex structure of the atom. Despite its shortcomings, the plum pudding model was a steppingstone in atomic theory, and Thomson was recognized for his contributions with a Nobel Prize in Physics in 1906 and a knighthood.