Atomic Models
No description yet. This curated deck is ready for daily study.
Card preview (5)
Democritus’ contribution to the atomic model
Democritus (5th century BC) was the first to imagine that matter is made of atoms.
John Dalton’s contribution to the atomic model
Dalton published the first fully scientific model of the atom in 1803. His theory included Democritus’ idea that everything is made of indivisible atoms (this would later be proved false.) Dalton proposed that atoms are not created or destroyed during chemical reactions, and that every atom of a given element is identical.
J.J. Thomson’s contribution to the atomic model
Thomson contributed that there were smaller pieces inside the atom in 1897. He discovered electrons, and that they have a negative charge. His model is called the plum pudding model. The plum pudding model shows a cloud of (positively charged) material peppered with electrons (negatively charged.)
Ernest Rutherford’s contribution to the atomic model
In 1909, Rutherford came to the conclusion that all of the positive charge in the atom was concentrated into the center, a place called the nucleus. He also found that the electrons were surrounding the nucleus.
Niels Bohr’s contribution to the atomic model
In 1913, Bohr was the first to propose that the electrons were orbiting the nucleus, and that each orbit represented different energy levels for electrons, with the lower energy (the lowest being two electrons) in the center, and the higher energy amounts on the outside.