Download Atom Models Timeline

Atom Models Timeline
To help you piece together the story of what we know about the "atom", you will be creating a
timeline depicting the development of the scientific model of the atom. It has been through new
discoveries by philosophers and scientists in chemistry, as well as physics, that the model of
the atom has expanded and changed over time. Your assignment is to research the major
contributors and significant discoveries that have impacted the atomic model and, from this
material, develop a timeline.
Requirements:
Your timeline MUST:
1. Match each of the 12 scientists and/or philosophers located in the tables below to key
dates and also their contributions to the atomic model.
2. Include pictures of atomic models at their respective year of discovery. Be sure to
clearly label key characteristics of these models (protons, neutrons, electrons, nucleus,
etc…):
 indivisible, solid sphere model
 quantum mechanical model
 nuclear or planetary model
 plum (raisin) pudding model
 orbit or Bohr model
3. Be chronological in its sequence, with the dates clearly shown (it need not be to scale),
and at a minimum include the information contained in the following tables.
4. Be neat and legible.
Deadlines and Guidelines:
 Your timeline is due on ____________________. 15 points will be deducted for every
day that it is late.
 Extra credit may be given for the inclusion of other atomic scientists and/or
philosophers. Additional scientists and/or philosophers that may be included are
Wolfgang Pauli, Leucippus of Miletus, Henri Becquerel, Francis Aston, and Amadeo
Avogadro. All required information for the original group of atomic scientists and/or
philosophers should be included. A maximum of 5 additional scientists may be included
for extra credit. 3 extra credit points will be awarded at for each additional scientist listed
with their major contribution and date of discovery.
 I strongly recommend using the websites listed below to identify key dates, as different
sources may have slightly different dates.
To help you with your timeline, mark the number of the scientist next to his
corresponding key date and contribution!
Key Scientists/Philosophers
Key Dates
1. Aristotle
~400 B.C.
2. Niels Bohr
mid 300’s B.C.
3. James Chadwick
1803
4. John Dalton
1897
5. Louis deBroglie
1900
6. Democritus of Adbera
1909
7. Werner Heisenberg
1909
8. Robert Millikan
1912
9. Max Planck
1924
10. Ernest Rutherford
1926
11. Erwin Schrödinger
1927
12. Joseph John Thomson
1932
Contributions
atom
• electrons travel in specified energy levels
• spectrum lines produced when electrons
move
• atomos- indivisible
• first to identify possibility of an atom
• smallest piece of matter
• measured charge of an electron
• oil drop experiment
• completed with Thomson
• “uncertainty principle”
• impossible to determine the position and
the momentum of a particle at the same
time
• electrons have properties of both waves
and particles
• group of waves named after this scientist
• showed mathematically that waves can
be used to describe electrons in atoms
• determined probability location of
electrons in atoms
• “cloud” model aka quantum mechanical
model
• Einstein used this scientist’s work to
study photons
• father of modern atomic theory
• 5 parts to theory
• includes elements are composed of
atoms
• also includes element’s atoms are
identical in mass
• proposed solid sphere model of the atom
• discovered electron
• described nature of cathode rays
• plum pudding model of atom
• four “elements”: earth, fire, air, water
• believed in reasoning instead of scientific
experiments
• dismissed Democritus’ atom idea as
“worthless”
• gold foil experiment
• atom has small positive nucleus,
remainder is empty space
• predicted existence of neutrons
• proposed planetary model of atom
• helped with the development of the
nuclear model
• discovered neutron
Helpful Websites:









http://library.thinkquest.org/19662/low/eng/ancient.html
http://www.aip.org/history/electron/jj1897.htm
http://regentsprep.org/Regents/physics/phys05/catomodel/ruther.htm
http://csep10.phys.utk.edu/astr162/lect/light/bohr.html
http://scienceworld.wolfram.com/biography/Dalton.html
http://library.thinkquest.org/19662/low/eng/neutrons.html
http://www.nobeliefs.com/atom.htm
http://www.juliantrubin.com/bigten/millikanoildrop.html
http://mhsweb.ci.manchester.ct.us/library/webquests/atomicmodels.htm
Rubric for Project
Scientists (60 pts): 5 points each for a correctly matched scientist to his correct key date and
contribution.
Points:
Timeline (40 pts)
Atomic
Models
10
Pictures of all
models are
present and
coupled with
their
respective
dates.
Chronological
in Sequence
Dates and
Information
(2 pts. for
each
scientist)
24
All dates,
scientists,
and
contributions
are clearly
marked on
the timeline.
8
Pictures of 4
models are
present and
coupled with
their
respective
dates.
6
4
2
Pictures of 3 Pictures of 2 Picture of 1
models are
models are
model is
present and
present and present and
coupled with coupled with coupled with
their
their
its
respective
respective
respective
dates.
dates.
date.
Timeline is
chronological.
22-16
14-8
6-2
0
Most dates, Some dates,
Few dates,
No dates,
scientists,
scientists,
scientists,
scientists,
and
and
and
and
contributions contributions contributions contributions
are clearly
are clearly
are clearly
are clearly
marked on
marked on
marked on
marked on
the timeline. the timeline. the timeline. the timeline.
Points:
TOTAL POINTS:
%
KEY
Key Scientists/Philosophers
1. Aristotle
2. Niels Bohr
3. James Chadwick
4. John Dalton
5. Louis deBroglie
6. Democritus of Adbera
7. Werner Heisenberg
8. Robert Millikan
9. Max Planck
10. Ernest Rutherford
11. Erwin Schrödinger
12. Joseph John Thomson
Contributions
2
atom
• electrons travel in specified energy levels
• spectrum lines produced when electrons
move
6
• atomos- indivisible
• first to identify possibility of an atom
• smallest piece of matter
8
• measured charge of an electron
• oil drop experiment
• completed with Thomson
7
• “uncertainty principle”
• impossible to determine the position and
the momentum of a particle at the same
time
5
• electrons have properties of both waves
and particles
• group of waves named after this scientist
11
• showed mathematically that waves can be
used to describe electrons in atoms
Key Dates
6 - ~400 B.C.
1 - mid 300’s B.C.
4 - 1803
12 - 1897
9 - 1900
10 - 1909
8 - 1909
2 - 1912
5 - 1924
11 - 1926
7 - 1927
3 - 1932
9
• Einstein used this scientist’s work to
study photons
•4
• father of modern atomic theory
• 5 parts to theory
• includes elements are composed of
atoms
• also includes element’s atoms are
identical in mass
• proposed solid sphere model of the atom
•1 2
• discovered electron
• described nature of cathode rays
• plum pudding model of atom
1
• four “elements”: earth, fire, air, water
• believed in reasoning instead of scientific
experiments
• dismissed Democritus’ atom idea as
“worthless”
10
• gold foil experiment
• atom has small positive nucleus,
remainder is empty space
• predicted existence of neutrons
• proposed planetary model of atom
3
• helped with the development of the
nuclear model
• determined probability location of electrons in
atoms
• “cloud” model aka quantum mechanical
model
• discovered neutron