Download History of Atomic Theory

History of Atomic Theory
Research the discoveries
and experiments of
scientists and their
contribution to “atomic
theory”
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Democritus & Dalton
Democritus (460 BC)
First to develop the
idea that matter was
made of “atoms”.
Dalton (1803)
Proposed the atomic
theory
atoms are indivisible
& indestructible
elements have
unique atomic
masses
Mendeleev (1869)
Developed the first basic
periodic table
Table was arranged by
atomic weight
was able to predict
elements which hadn’t
been found
J.J. Thomson (1898)
• Discovered electrons (-e)
• Atoms have — & + charges
Rutherford (1911)
Discovered the
positively charged
nucleus
shot positively
charged particles
through gold foil
electrons moved in
circles
Bohr (1913)
Electrons move in
specific energy levels
(orbits) around the
nucleus
Schrodinger (1926)
Described electrons
as waves
Electron cloud
Chadwick (1932)
Neutrons (and
protons) made up
the nucleus
Evolution
of the
Atom
Evolution of the Atom