Transcript 24-2 History of Atoms Poster Project PPT_2

Atomic Theory Poster
• Your job: Create a poster on your two
assigned scientists
• Answer all 5 Questions for BOTH as shown
on your direction sheet!
• For #5, either draw a picture of their
experiment, their “atom” model or BOTH
• Start by finding out the basics using the
text book! Then go online to add to it.
• All scientists are IN the book (look in the index
by LAST name). After getting info from book,
look online as needed!
• (Schrodinger not in book)
When we are finished with the
posters or presentation
1. Write group members name’s and
period # on poster or title slide
Gallery Viewing to answer notes sheet
2. Go around to the different posters or
computers and fill out the table on
your sheet.
The following slides are for review,
catch up for absent students, or help
filling in the gaps from the student
presentations or posters
1808: John Dalton
• Dalton’s atomic model is
called the “Billiard Ball
Model”
• All bodies are made of
extremely small particles,
or atoms of matter
bound together by a
force of attraction
• The ultimate particles of
all homogeneous bodies
are perfectly alike in
weight, figure, etc.
Mendeleev first trained as a teacher in the Pedagogic Institute
of St. Petersburg before earning an advanced degree in
chemistry in 1856.
Dmitri Ivanovich Mendeleev (1834-1907)
We will never be able to attribute to a single
individual the development of the basic
building blocks of writing. Yet we do know the
name of the man who devised the method of
classifying the basic building blocks of matter.
When Mendeleev became a professor of
general chemistry at the University of St.
Petersburg, Russia, he literally wrote the
book on physical science. That textbook,
written between 1868 and 1870, would
provide a framework for modern chemical
and physical theory.
• Mendeleev’s
Periodic Table
Thomson’s Atomic Model
J. J. Thomson
Thomson believed that the electrons
were like plums embedded in a
positively charged “pudding,” thus it
was called the “plum pudding” model.
From his experiments, Thompson concluded that a cathode
ray consists of a beam of negatively charged particles
(electrons) and that electrons are constituents of all matter.
Subatomic Particles
Particle
Charge
Mass (g)
Location
Electron
(e-)
-1
9.11 x 10-28
Electron
cloud
Proton
(p+)
+1
1.67 x 10-24
Nucleus
Neutron
(no)
0
1.67 x 10-24
Nucleus
Rutherford’s Findings
Observations/Evidence:
Most of the particles passed right through
 A few particles were deflected
 VERY FEW were greatly deflected
http://www.youtube.com/watch?v=bSEOOMs5VNU
http://phet.colorado.edu/en/simulation/rutherford-scattering
“Like howitzer shells bouncing off of tissue paper!”
Inference/Conclusions:
• The nucleus is small
• The nucleus is dense
• The nucleus is positively
charged
Ernest Rutherford’s
Gold Foil Experiment - 1911
Alpha particles are helium nuclei The alpha particles were fired at a thin
sheet of gold foil
 Particles that hit on the detecting
screen (film) are recorded

You can compare the head of a pin to
the diameter of a stadium to think
about atom size….
http://www.pbslearningmedia.org/resource/phy03.sci.phys.matter.atoms/atoms-the-space-between/
• The diameter of a pinhead is 100,000 times smaller than the diameter of a
stadium.
• Likewise the diameter of the nucleus of an atom is 100,000 times smaller
than the diameter of an atom.
• Quick field trip, follow me outside.
Bohr's greatest contribution to modern
physics was the atomic model. The Bohr
Neil's Bohr was the first to discover that
electrons travel in separate orbits around
the nucleus and that the number of
electrons in the outer of an element
orbit determines the properties (1922)
James Chadwick
• 1932
• discovered neutron in the nucleus.
The Modern Theory of the
Atom
Erwin Schrödinger
http://www.fearofphysics.com/Atom/atom3.html
http://www.youtube.com/watch?v=IOYyCHGWJq4
• Electrons
travel in
regions called
“electron
clouds”
• You cannot
predict
exactly where
an electron
will be found
What is the structure of
an atom?
Bohr Model
Schrödinger Model
“Planetary Model”
“Electron Cloud Model”
Exit Task
• From memory, not looking at the
worksheet sketch the models of the
atom for each of the scientists
presented today.
Quick atomic
model review
and the
scientists
credited with
the model
Chadwick 1932,
nucleus
A review:
http://www.youtube.com/wa
tch?v=njGz69B_pUg&featu
re=related
http://phet.colorado.edu/en/
simulation/hydrogen-atom