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The basic unit of matter.
Earliest model
John Dalton
No internal structure .
(cannonball) model
J.J. Thomson - + -- + -
Electrons and positive charges
+ - + - +
model disperse throughout the atom. - + - + - +
Ernest Rutherford
A small and dense positive (+) empty space
(nuclear) model nucleus.
Most of atom is empty space. +
Electrons revolve around the
nucleus.
(c) E3 Scholastic Publishing
Niels Bohr
Electrons in specific orbit .
(planetary) model Orbits have fixed energy. e- +
Orbits are the electron shells.
orbit (electron shells)
Work of many Scientists over
hundreds of years.
(electron-cloud) model The current model of the atom.
Small, dense, positive nucleus. +
Protons and neutrons in the nucleus.
Electrons in orbital outside the nucleus.
Orbital
current model
Probable location of finding an electron with a
specific energy.
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