1. Bell Ringer
Get a piece of paper and fold it so that you have three columns
On one column you will write what you already know about the structure of atoms
On the second column you will write down what you would like to learn about atoms and their structure
On the third column you will write down what you learned today about the structure of atoms

2. Atomic Structure

3. Early History of Science
Greeks (400 BC): First to explain why chemical changes occur

4. Early History of Science
Greeks (400 BC): Is matter infinitely divisible? Or made of small indivisible particles?
Demokritos and Leucippos ( BC):
Matter is made of indivisible particles (atomos; which in greek means undivisible)

5. For the next 2000 years
Alchemy

6. Foundations of modern Chemistry
George Bauer ( )
Metals from metal ores
Robert Boyle ( )
First “Chemist” to perform truly quantitative experiments. He carefully measured the relationship between pressure and volume of air

7. Foundations of modern Chemistry
Antoine Lavoisier ( )
Father of modern Chemistry
French chemist who explained what happens during combustion reactions and verified the Law of conservation of mass
Published the first Chemistry textbook in 1789

8. Scientists follow the lead
Joseph Proust ( )
French guy who, following Lavoisier’s way of carefully measuring during an experiment, came out with the principle of the constant composition of compounds
Later known s the Law of definite Proportions
A given compound always contains the same proportion of elements by mass

9. Scientists follow the lead
John Dalton( )
Analyzing the quantities of different compounds came out with the Law of multiple proportions
When two elements form a series of compounds, the ratios of the masses of the second element that combine with 1 gram of the first element can always be reduced to whole numbers
First Atomic Theory
Each element is made up of tiny particles called atoms
The atoms of a given element are identical
Chemical compounds form when atoms of different elements combine. A given compound always has the same number of and types of atoms.
Chemical reactions involve reorganization of the atoms-change in the way they are bound togethre. The atoms themselves are not changed.

10. Scientists follow the lead
Joseph Gay Lussac ( French)
Amadeo Avogadro ( Italian)
Studied gases and came out with Avogadro’s hypothesis
At the same temperature and pressure, equal volumes of different gases contain the same number of particles.

11. Scientists follow the lead
J.J. Thomson( English Physicist)
Discovered electrons using a cathode-ray tube
Led him to come out with the plum pudding model of the atom

12. Scientists follow the lead
Robert Milikan ( )
In 1909 at the university of Chicago, performing very clever experiments with oil drops he was able to determine the mass of an electron. (9.11x10^-31 kg)
Ernest Rutheford ( New Zealand)
Proved the plum pudding model wrong and discovered that atoms have a positive center.

13. Modern View of Atomic Structure

14. Modern View of Atomic Structure