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Atomic Theory

Atomic Theory . The development of our knowledge of Chemistry. 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 ”. The detractors:.

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Atomic Theory

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  1. Atomic Theory The development of our knowledge of Chemistry

  2. 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”

  3. 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!!!!

  4. 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….

  5. 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.

  6. 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!!!!!

  7. 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

  8. 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!

  9. 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!

  10. Ernest Rutherford • In early 1900’s (1920) or so, ErnestRutherford did an experiment famously know as the “Gold Foil Experiment” • It looked like this…..

  11. His experiment showed that there was something in the atom that: • Had mass • Had a positive charge • It was the proton!!!!

  12. The atom is mostly empty space! • If I found a good visual to cut and paste…. • If not……

  13. James Chadwick • In about 1930, James Chadwick did some experiments similar to JJ Thomson. • He used a cathode ray tube and…. • Discovered the Neutron!

  14. 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

  15. 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!

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