Atomic theory history timeline.

Democritus (460-470 B.C.) the first person to suggest that matter could not be infinitley divided. Also, the first person to come up with the term "atomos" now known as atoms. "Atoms can not be created, destroyed, or further divided." But unfortunately, he could not figure out what holds atoms together.

Aristotle (384-322 B.C.) disagreed with Democritus' idea that atoms move through empty space. He completely denied the exstience of atoms due to his personal beliefs about nature. His ideas overpowered Democritus'.

James Dalton (1766-1844) an English scholar, who marks the beginning of the development of the modern atomic theory. He took Democritus' ideas about matter and revised them based off of his beliefs and research. Revised the term "atom".

Sir William Crookes (1861-1880) noticed a green flash of light within a cathode ray tube while working in a dark labatory. Some type of radiation striking a zinc-sulfide coating inside the tube. This discovery led to the television hence "gonna go watch the tube."

Physicist J.J. Thompson (1856-1940), designed many CRT experiments to determine the ratio of the particle's charge to its mass. He concluded that the mass of the particle was much less than that of the Hydrogen atom, which disproved Daltons theory that atom are indivisble. In 1906, all of his work had paid off and he won the nobel prize for his research, the discovery of the electron and the first subatomic paticle.

American Physicist Robert Millikan (1868-1953), a brilliant man that designed an oil drop apparatus to determine the charge of the electron. He concluded that the magnitude of the charge of the electron.

Ernest Ruford (1871-1937) studied how positivley charged a-particles ineracted with solid matter. He came up with an experiment to see if a- particles would be deflected if they passed through a thin sheet of gold foil. After experimenting he came to the conclusion that Thompson's plum pudding experiment was incorrect. He said there has to be a place for the positive charge and then came the center of an atom, the nucleus.

James Chadwick and English Physicist (1891-1974) demonstrated that the nucleus t another nuetral subatomic particle called the neutron. Chadwick won the 1935 nobel prize for his discovery of the neutron.