the development of our knowledge of chemistry. a greek philosopher who, in about 300 bce suggested...

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ATOMIC THEORY The development of our knowledge of Chemistry

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Page 1: The development of our knowledge of Chemistry.  A greek Philosopher who, in about 300 BCE suggested that the stuff around us ( matter) is composed of

ATOMIC THEORYThe development of our knowledge of Chemistry

Page 2: The development of our knowledge of Chemistry.  A greek Philosopher who, in about 300 BCE suggested that the stuff around us ( matter) is composed of

Democritus

A greek Philosopher who , in about 300 BCE suggested that the stuff around us ( matter) is composed of very small little particles.

He called them “Atomos”

Page 3: The development of our knowledge of Chemistry.  A greek Philosopher who, in about 300 BCE suggested that the stuff around us ( matter) is composed of

The detractors:Most scientists of the day, thought Democritus must have been…Smoking crack or something!They all “knew” that matter was made up of the four elements:Earth, Wind, Fire, and Water!!!!

Page 4: The development of our knowledge of Chemistry.  A greek Philosopher who, in about 300 BCE suggested that the stuff around us ( matter) is composed of

John Dalton

In the Late 1700’s to early 1800’s John Dalton suggested to the world that:

Matter is composed of small little particles …. Called “atoms”

He is known as the Father of Modern Chemistry

He did some experimentation to help him come up with the 4 principles of matter….

Page 5: The development of our knowledge of Chemistry.  A greek Philosopher who, in about 300 BCE suggested that the stuff around us ( matter) is composed of

1. All elements are made up of small indivisible particles called “atoms”

2. Atoms of one element are “identical” but atoms of other elements are different from the others. ( all Au atoms are “the same” all Al atoms are “the same” but Al and Au are different)

3. Atoms can combine in small whole number ratios to form compounds

4. Atoms can be rearranged, and recombined when they form compounds, but they are never changed.

Page 6: The development of our knowledge of Chemistry.  A greek Philosopher who, in about 300 BCE suggested that the stuff around us ( matter) is composed of

The detractors….

A great many “scientists” and philosophers thought Dalton must have been….

Smoking crack or something!!!!!

Because they all knew that matter was composed of Earth, Wind, Fire, and Water!!!!!

Page 7: The development of our knowledge of Chemistry.  A greek Philosopher who, in about 300 BCE suggested that the stuff around us ( matter) is composed of

Dimitri Mendeleev

By the mid 1800’s there were about 70 elements known.

Mendeleev came up with a way to organize them, based on their atomic mass.

He essentially created the 1st periodic table

Page 8: The development of our knowledge of Chemistry.  A greek Philosopher who, in about 300 BCE suggested that the stuff around us ( matter) is composed of
Page 9: The development of our knowledge of Chemistry.  A greek Philosopher who, in about 300 BCE suggested that the stuff around us ( matter) is composed of

JJ Thomson

In 1897 JJ Thomson used a cathode ray tube that looked kinda like this…..

And discovered the electron!!!!! Other scientists working to study the

atom determined that the electron must have a mass of about 9.1 x 10-28 g

current value: 9.109 x 10-28g!

Page 10: The development of our knowledge of Chemistry.  A greek Philosopher who, in about 300 BCE suggested that the stuff around us ( matter) is composed of
Page 11: The development of our knowledge of Chemistry.  A greek Philosopher who, in about 300 BCE suggested that the stuff around us ( matter) is composed of

Neils Bohr

In about 1913, Neils Bohr came up with the idea that electrons revolve around the atom in orbits around the atom. Similar to the way planets orbit a star

We now know that this Is not exactly how it is!

Page 12: The development of our knowledge of Chemistry.  A greek Philosopher who, in about 300 BCE suggested that the stuff around us ( matter) is composed of

Ernest Rutherford

In early 1900’s (1920) or so, Ernest Rutherford did an experiment famously know as the “Gold Foil Experiment”

It looked like this…..

Page 13: The development of our knowledge of Chemistry.  A greek Philosopher who, in about 300 BCE suggested that the stuff around us ( matter) is composed of

His experiment showed that there was something in the atom that:

Had mass Had a positive charge It was the proton!!!!

Page 14: The development of our knowledge of Chemistry.  A greek Philosopher who, in about 300 BCE suggested that the stuff around us ( matter) is composed of

The atom is mostly empty space! If I found a good visual to cut and

paste…. If not……

Page 15: The development of our knowledge of Chemistry.  A greek Philosopher who, in about 300 BCE suggested that the stuff around us ( matter) is composed of
Page 16: The development of our knowledge of Chemistry.  A greek Philosopher who, in about 300 BCE suggested that the stuff around us ( matter) is composed of

James Chadwick

In about 1930, James Chadwick did some experiments similar to JJ Thomson.

He used a cathode ray tube and…. Discovered the Neutron!

Page 17: The development of our knowledge of Chemistry.  A greek Philosopher who, in about 300 BCE suggested that the stuff around us ( matter) is composed of

Summer 2012

The Higgs Boson was discovered? Postulated in about 1965 or so, The Higgs

Boson is some magical and mythical “thingy” that helps give matter its mass.

Some, including scientists, refer to it as “The God Particle!” as it will perhaps help us understand matter a little bit better

A few days Later, Mr. Jury still doesn’t understand what the

Higgs Boson is all about

Page 18: The development of our knowledge of Chemistry.  A greek Philosopher who, in about 300 BCE suggested that the stuff around us ( matter) is composed of

What problems/ obstacles did the scientists have when they were trying to figure out what “stuff’ ( matter) was made of?

What technological barriers did they face?

What do doctors need to do when they are trying to help cure a sick patient?

Are doctors always successful? Explain!