What is the history of atomic theory?

What is the history of atomic theory?

Atomic theory has evolved significantly since ancient times, starting with Democritus in the 5th century BC, who proposed that matter is made up of indivisible particles called atoms. In the early 19th century, John Dalton formulated the first modern atomic theory, introducing the idea that atoms combine in specific ratios to form compounds. Later, J.J. Thomson discovered the electron in 1897, leading to the plum pudding model. Ernest Rutherford's gold foil experiment in 1909 revealed the nucleus, and Niels Bohr further refined the model in 1913. Quantum mechanics in the 20th century brought a deeper understanding of atomic structure.

Who were the key figures in the development of atomic theory?

Key figures include Democritus, John Dalton, J.J. Thomson, Ernest Rutherford, and Niels Bohr. Each contributed crucial insights that shaped our understanding of atomic structure.

How did the discovery of the electron change atomic theory?

The discovery of the electron by J.J. Thomson challenged the idea of the atom as indivisible. It led to the realization that atoms are composed of smaller particles, prompting the development of new models of atomic structure.

What is the modern understanding of atomic theory?

Modern atomic theory incorporates quantum mechanics, describing atoms as having a nucleus surrounded by a cloud of electrons. It emphasizes the probabilistic nature of electron positions and the interactions between particles.