Chapter 11
Introduction to
Atoms
Section 1–Development of the Atomic Theory
I. Development of the Atomic Theory
A. Atom- the smallest particle into which
an element can be divided and still be
the same substance.
1. Atoms make up elements.
2. Elements make up compounds.
3. Atoms make up all matter, and are
called the “building blocks of
matter”.
What’s bigger? A cell or an atom?
(http://micro.magnet.fsu.edu/primer/java/scienceopticsu/powersof10/index.htm
Section 1–Development of the Atomic Theory
B. Democritus, Greek philosopher around
440 B.C.
1. If you kept cutting a coin in ½ you would
eventually end up with an very tiny, uncuttable
piece, this he called an atom. Meaning indivisible.
2. Atom- from the Greek word atomos
3. Atoms are always moving and join
together to form different materials.
http://images.google.com/imgres?imgurl=http://periodictable.com/pages/pix/democritus.gif&imgrefurl=http://periodictable.com/pages/AA
E_Democritus.html&h=326&w=268&sz=55&tbnid=jUyFAQFkreYJ:&tbnh=113&tbnw=93&start=1&prev=/images%3Fq%3Ddemocritus
%26hl%3Den%26lr%3D%26sa%3DG
Random vocab - propose
Section 1–Development of the Atomic Theory
4. Aristotle, 380 B.C., disagreed and
because of his influence Democritus’
ideas were ignored.
Ode to the ODG
( to the tune of the wakishika canoers we travel on the lake)
Democritus’s atom – smallest piece could
not be cut. And each atom was different,
like Lucky charms that I eat up.
* The atom- It’s history is long. But without
these old dead guys
the chemistry is gone
Section 1–Development of the Atomic Theory
C. Dalton, British school teacher in 1803 A.D.
1. Dalton’s Atomic Theory
a. All substance are made of atoms
b. Atoms cannot be created, divided,
destroyed
c. Atoms of the same element are
exactly alike
d. Atoms of different elements are
different.
e. Atoms join with atoms to make
substances.
2. Dalton’s theory was not totally correct.
http://www.poolndarts.com/images/misc/35.jpg
Democritus’s atom – smallest piece could not be cut.
And each atom was different, like Lucky charms that
I eat up.
* The atom- It’s history is long. But without these old
dead guys
the chemistry is gone
Dalton was a teacher who did science on the side.
he discovered rules for atoms, some of which we still
abide. *
Section 1–Development of the Atomic Theory
D. J.J. Thomson, British scientist in 1897.
1. Discovered small particles inside the
atom.
2. Cathode-Ray tube experiments
a. Some part of the atom was attracted to
a positive plate so the unknown particle
had to have a negative charge.
b. Thompson called these corpuscles,
today we call them electrons –
negatively charged particles found in all
atoms.
Random vocab- illustrate
J.J Thomson movie
Section 1–Development of the Atomic Theory
3. Model- a representation of an object or
system. A picture of what a theory
explains.
a. plum-pudding model
b. chocolate-chip-ice-cream model
Plum pudding model
for the atom
http://members.tripod.com/craigjm/Atom4.jpg
Plum pudding
Blueberry muffin
http://www.fotosearch.com/comp/FDS/FDS101/Blueberry-Muffin-Single.jpg
http://www.zarbo.co.nz/products/Christmas/christmas%20pudding%20lg.jpg
Democritus’s atom – smallest piece could not be cut.
And each atom was different, like Lucky charms that
I eat up.
* The atom- It’s history is long. But without these old
dead guys
the chemistry is gone
Dalton was a teacher who did science on the side.
he discovered rules for atoms, some of which we still
abide. *
Thomson found electrons, like plums in the pudding.
and for this negativity the Nobel prize he’d win. *
Section 1–Development of the Atomic Theory
E. Rutherford’s Gold Foil Experiment
1. Atom may not be just a soft “blob” of
material
2. New Atomic Model (1911)
a. Nucleus- dense, positively charged
central region of an atom.
b. Draw a Rutherford Atom
Gold foil experiment-Video
Add”l
Rutherford movie
http://cwx.prenhall.com/petrucci/medialib/medi
a_portfolio/text_images/006_RUTHERFORD.
MOV
Democritus’s atom – smallest piece could not be cut.
And each atom was different, like Lucky charms that
I eat up.
* The atom- It’s history is long. But without these old
dead guys
the chemistry is gone
Dalton was a teacher who did science on the side.
he discovered rules for atoms, some of which we still
abide. *
Thomson found electrons, like plums in the pudding.
and for this negativity the Nobel prize he’d win. *
Rutheford’s experiments shot charges at gold foil.
he discovered then, the nucleus,
for all his work and toil.*
Section 1–Development of the Atomic Theory
F. Bohr’s Model of the Atom
1. Electrons travel around the
nucleus in definite paths.
2. Electrons are located in
specific levels that are a
certain distance from the
nucleus.
3. Electrons can jump from
one level to the next and
back
4. Rungs of a ladder analogy.
http://members.aol.com/profchm/bohr.gif
http://ocw.mit.edu/NR/rdonlyres/Global/B/BBC8A015-019C-4D01-A31B-4E440BB822B3/0/chp_ruthbohr1.jpg
Bohr model video
www.shodor.org/.../ compchem/slides/slide23.html
Democritus’s atom – smallest piece could not be cut.
And each atom was different, like Lucky charms that I eat up.
* The atom- It’s history is long. But without these old dead guys
the chemistry is gone
Dalton was a teacher who did science on the side.
he discovered rules for atoms, some of which we still abide. *
Thomson found electrons, like plums in the pudding.
and for this negativity the Nobel prize he’d win. *
Rutheford’s experiments shot charges at gold foil.
he discovered then, the nucleus,
for all his work and toil.*
Neils Bohr discovered that electrons all had paths.
and the energy the electron had determines where its at.*
There are a couple dead guys who are not on the test.
They discovered protons and neutrons in the nucleus*
Section 1–Development of the Atomic Theory
G. Schrödinger and Heisenberg
1. electron clouds- regions around a
nucleus that an electron is likely to be
found in.
(6 box poster designed by students showing
name, model and how it changed from
previous model)
http://www.colorado.edu/physics/2000/images/electron_clouds/o320a.gif
http://scholar.lib.vt.edu/ejournals/SPT/v8n2/images/hennig_fig12.jpg
Electron cloud model video
Ode to the ODG
( to the tune of the folk song “Sarasponda”)
Democritus’s atom – smallest piece could not be cut.
And each atom was different, like Lucky charms that I eat up.
* The atom- It’s history is long. But without these old dead guys
the chemistry is gone
Dalton was a teacher who did science on the side.
he discovered rules for atoms, some of which we still abide. *
Thomson found electrons, like plums in the pudding.
and for this negativity the Nobel prize he’d win. *
Rutheford’s experiments shot charges at gold foil.
he discovered then, the nucleus, for all his work and toil.*
Neils Bohr discovered that electrons all had paths.
and the energy the electron had determines where its at.*
There are a couple dead guys who are not on the test.
They discovered protons and neutrons in the nucleus*
Then we come to Schroedinger the modern theory, now.
The Electrons now are located in a probability cloud. *