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/AAE_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.

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

Ode to the ODG ( to the tune of the wakishika canoers we travel on the lake)

Section 1–Development of the Atomic TheoryC. 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 goneDalton 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.

J.J Thomson movie Random vocab- illustrate

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 modelb. chocolate-chip-ice-cream model

http://www.zarbo.co.nz/products/Christmas/christmas%20pudding%20lg.jpghttp://www.fotosearch.com/comp/FDS/FDS101/Blueberry-Muffin-Single.jpghttp://members.tripod.com/craigjm/Atom4.jpg

Plum pudding Blueberry muffinPlum pudding model for the atom

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 goneDalton 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

http://cwx.prenhall.com/petrucci/medialib/media_portfolio/text_images/006_RUTHERFORD.MOV

Add”l Rutherford movie

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 goneDalton 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 TheoryF. 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

www.shodor.org/.../ compchem/slides/slide23.html http://ocw.mit.edu/NR/rdonlyres/Global/B/BBC8A015-019C-4D01-A31B-4E440BB822B3/0/chp_ruthbohr1.jpg

Bohr model video

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 goneDalton 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://scholar.lib.vt.edu/ejournals/SPT/v8n2/images/hennig_fig12.jpg

http://www.colorado.edu/physics/2000/images/electron_clouds/o320a.gif

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 guysthe 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. *