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Democritus
He bilieved that all matter consisted of extremely small particles called atoms.
He believed a solid's atom were rough and prickly. whike, liquid's atoms were round and smooth, -
John Dalton.
Dalton's atomic theory was that; all matter is made up of individual particles called atoms, which cannot be divided.
(Picture on side of what he used to explain his atom's theory.) -
J.J. Thomson.
His experiments provided the first evidence that atoms are made of even smaller particles. -
Hantaro Nagaoka
Suggested that an atom has a central nucleus. Electron's move in orbit like the rings around Saturn. -
Ernest Rutherford.
according to Rutherford's model, all of an atom's positive charge is concentrated in its nucleus. -
Neils Bohr.
In Niels Bohr's model, the electros move in spherical orbits at fixed distances from the nucleus. An electron in an atom can move from one energy level to another when the atom gains or losses energy. -
Erwin Schrödinger.
Schroödinger develops mathmaticla equations to describ the motion of electrons in atoms. His work leads to the electron model.
The electron cloud is a visual model of the probable locations of electrons in an atom. The probablility of finding an atom is higher in he denser regions of the cloud. -
James Chadwick.
James Chadwick, a British physicist, confirms the existance of neutrons, which have no charge. Atomic nuclei contain neutrons and positively charged protons.
