Download History of the Atom - Birmingham City Schools

History of the Atom
Democritus
400 BC
John Dalton
1800’s
J. J. Thompson
1897
Major
Contribution
Major Contribution
Transformed _____________
ideas on atoms into a
_______________________
Major Contribution
Discovered the ___________
Proposed the ____
______________
Conducted the ___________
______________ experiment
Dalton’s Atomic Theory
Greek philosopher
1) All _________ is made of
tiny ______________
particles called __________
- called smallest
unit of matter
_______________
2) The atoms of the same
element are ______________,
those of different elements are
______________
-competed with
the ideas of
Aristotle which
were:
3) Atoms of different
____________ combine in
small, _____________ ratios
to form _________________
Other Information:
That _______
substances are
made of 4
_____________.
1.
2.
3.
4.
__________
__________
__________
__________
4) Chemical reactions involve
the ___________________ of
atoms. No new atoms are
________________________
(Law of _________________
_______________________)
Robert Millikan
1909
Major
Contribution
Determined the
____________and
______________
of the electron
Cathode Ray Tube Experiment
By adding an _________________
he found that the moving pieces
were _____________________
Use the diagram above to sketch the
results of Thomson’s experiment
Plum pudding model
Displays electrons
______________ in a
sphere of __________ charged
material
Use the diagram on the
left to sketch the model
Conducted ______
_______________
by measuring the
effect of an
electric field on
very small oil
droplets.
From the _______
of the drop and
the ________on
the plates, he
calculated the
____________on
an _____________
History of the Atom Continued
Gold Foil Experiment
Expected Results
Ernest Rutherford
1912
Neils Bohr
1913
Major Contribution
Discovered the
___________________
Major Contribution
Proposed that an
______is found only in
specific circular paths, or
_______, around the
_____________
Gold Fold Experiment
Actual Results
Rutherford’s Model
Atoms
of gold
foil
Au foil
Au Foil
Bright Line spectra
experiment
Bohr’s Model
Screen
Use the diagram
above to sketch the
EXPECTED behavior of
the alpha particles
Screen
Use the diagram
above to sketch the
ACTUAL behavior of
the alpha particles
Use the diagram of the
above to sketch the
behavior of the alpha
particles according to
Rutherford’s proposed
model
Referred to as ________
_________ because
electrons move around
the ____________ like
planets around the
________
Rutherford made 2 major conclusions from his Gold Foil Experiment:


The ______________ is made up of mostly
______________________
The atom contains a ____________________________ piece at
center
What experimental evidence led to Rutherford’s conclusion?
Use the diagram above
to draw a Bohr model of
a Lithium Atom
Ernest Schrodinger &
Werner Heisenberg
1926
Sir James
Chadwick
1932
Major Contribution
Modified Bohr’s
Model to the Electron
Major
Contribution
Confirmed the
existence of
__________in the
______________
_
_______ Model
Quantum Mechanical
Model (AKA. Electron
Cloud Model )
Viewed atoms as
__________ within
__________.
Unlike the Bohr
model, this model
does ______ define
the exact _________
of an electron, but
rather, predicts the
_________ of the
location of the
electron.
Modern Atomic
Model
-The _________
is mostly
_________ space
-The atom
consists of
_______ regions
-Nucleus in
center and
contains ______
and __________
-The __________
_______ is the
region where
electrons in
areas of high
______________
called atomic
______________