HISTORY OF THE

ATOM

interactive lecture – kandace little

LET’S MAKE A FIRST WORD BASED ON WHAT WE KNOW

FIRST WORD: ATOM

A

T

O

M

I’m going to take you back to 350 B.C….

THE BEGINNINGS

Aristotle

earth

…

water

…

fire

…

air

…

Aristotle asks you: “Can you deny that these

are the fundamental elements of the earth, Ruler?”

Your reply? Alas, after deep thinking, you are convinced

that this wise philosopher is correct. Aristotle has made observations about life and this is his THEORY to explain those observations.

…

Jumping to 300 A.D...

GOLD

Tin

Lead

The alchemists are inspired by Aristotle’s

ideas and are trying to turn cheap metals into GOLD!

The news article says that even though the Pope issued that no gold-making occurred, the gold business continued.

However, despite the alchemists efforts, they were unsuccessful in changing cheap metals into gold.

…

A little later on..

GOLDBREAKING NEWS: NEW THEORY FOUND!

-All matter is made of atoms.-Atoms of an element are identical.-Each element has different atoms.-Atoms of different elements combine in constant ratios to form compounds.-Atoms are rearranged in reactions.

LAW OF CONSERVATION OF MASS

Boyle, Crookes, Becquerel, Thomson, Rutherford, Chadwick

John Dalton = new hero

2 p+

2 n0

John Dalton states the Atomic Theory

Dalton’s “Billiard Ball”

model

Atoms are solid and indivisible.

Negative electrons in a positive framework

Thompson Plum Pudding model

To show this is a positive framework

Atoms are mostly empty space.

Negative electrons orbit a positive nucleus.

The Rutherford Model

Putting all this together, we get Bohr-

Rutherford diagrams that look like this:

Bohr-Rutherford Model

2 p+

2 n0 3 p+

4 n0

LET’S MAKE A LAST WORD BASED

ON WHAT WE KNOW NOW

LAST WORD: ATOM

A

T

O

M

Chalkbored found at www.chalkbored.com

History of Chemistry found at http://www.columbia.edu/itc/chemistry/chem-c2507/navbar/chemhist.html

References