How did J.J. Thomson's discovery of the electron challenge John Dalton's atomic model?

John Dalton’s atomic model, developed between 1803 and 1808, was built on the premise that atoms were the smallest, indivisible building blocks of matter that could not be created, destroyed, or divided into smaller pieces.12

J.J. Thomson’s 1897 discovery of the electron fundamentally challenged this model by proving that the atom was not a homogeneous, indivisible particle, but rather a complex structure containing smaller, subatomic components. Because Dalton’s model did not account for electrical charge, Thomson’s findings demonstrated that atoms were divisible and contained negatively charged particles.31

This discovery rendered the long-standing conception of the atom as an immutable, solid sphere untenable. Consequently, Thomson used his research to support the "plum-pudding" model, which proposed that electrons were embedded within a sphere of positively charged matter, marking the first major shift away from Dalton’s original theory toward a modern understanding of atomic structure.3241