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John Dalton
pictures atoms as tiny, indestructible particles, with no internal structure. -
J.J. Thompson
British scientist, discovers the electron. later leads to his plumpudding model. pictures electrons embedded in a sphere of positive electrical charge. -
Hantaro Nagaoka
japanese physicist, suggests that an atom has a central nucleus. Electrons move in orbits like the rings around saturn -
Atomic orbitals
each energy sublevel corresponds to an orbital of a different shape, which describes where the electron is likely to be found. -
Ernest Rutherford
An atom has a small, dense, positively charges nucleus. Electrons move around the nucleus. -
Bohr model
proposed that an electron is found only in specific circular paths, or orbits, around the nucleus. -
Louis de Broglie
moving particles like electrons have some properties of waves. Within a few years, experimental evidence supports the idea -
Quantum mechanical model
determines the allowed energies an electron can have and how likely it is to find the electron in various locations around the nucleus. -
Erwin Schrodinger
develops mathematical equation to describe the motion of electrons in atoms. His work leads to the electron cloud model. -
James Chadwick
confirms the existence of neutrons, which have no charge. Atomic nuclei contain neutrons and positively charges protons.