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GSCI 163 Lecture 2. Atomic theory What are things made of? Imagine dividing an object into smaller...
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Transcript of GSCI 163 Lecture 2. Atomic theory What are things made of? Imagine dividing an object into smaller...
![Page 1: GSCI 163 Lecture 2. Atomic theory What are things made of? Imagine dividing an object into smaller and smaller units. Is there a limit to how much we.](https://reader035.fdocuments.in/reader035/viewer/2022070401/56649f165503460f94c2b875/html5/thumbnails/1.jpg)
GSCI 163
Lecture 2
![Page 2: GSCI 163 Lecture 2. Atomic theory What are things made of? Imagine dividing an object into smaller and smaller units. Is there a limit to how much we.](https://reader035.fdocuments.in/reader035/viewer/2022070401/56649f165503460f94c2b875/html5/thumbnails/2.jpg)
Atomic theory
• What are things made of?
Imagine dividing an object into smaller and smaller units. Is there a limit to how much we can divide?
![Page 3: GSCI 163 Lecture 2. Atomic theory What are things made of? Imagine dividing an object into smaller and smaller units. Is there a limit to how much we.](https://reader035.fdocuments.in/reader035/viewer/2022070401/56649f165503460f94c2b875/html5/thumbnails/3.jpg)
Atom
• Means “uncuttable”. Democritus (460-362 BC)
![Page 4: GSCI 163 Lecture 2. Atomic theory What are things made of? Imagine dividing an object into smaller and smaller units. Is there a limit to how much we.](https://reader035.fdocuments.in/reader035/viewer/2022070401/56649f165503460f94c2b875/html5/thumbnails/4.jpg)
John Dalton (1766 – 1844)
• All matter is made of atoms• Atoms cannot be created or destroyed.• All atoms of a given element are identical in
mass and properties. Different elements differ from each other because they are made of different atoms.
• Compounds are formed by the combination of two or more kinds of atoms in precise ratios.
• A chemical reaction is a rearrangement of atoms.
![Page 5: GSCI 163 Lecture 2. Atomic theory What are things made of? Imagine dividing an object into smaller and smaller units. Is there a limit to how much we.](https://reader035.fdocuments.in/reader035/viewer/2022070401/56649f165503460f94c2b875/html5/thumbnails/5.jpg)
Is the atom indivisible?
• J.J. Thompson – discovery of the electron 1897.
The cathode ray tube
![Page 6: GSCI 163 Lecture 2. Atomic theory What are things made of? Imagine dividing an object into smaller and smaller units. Is there a limit to how much we.](https://reader035.fdocuments.in/reader035/viewer/2022070401/56649f165503460f94c2b875/html5/thumbnails/6.jpg)
What is the electron?
• Robert A. Millikan in 1906 measured the charge of a single electron
![Page 7: GSCI 163 Lecture 2. Atomic theory What are things made of? Imagine dividing an object into smaller and smaller units. Is there a limit to how much we.](https://reader035.fdocuments.in/reader035/viewer/2022070401/56649f165503460f94c2b875/html5/thumbnails/7.jpg)
The model of the atom at this point
• Positive and negative charges mixed like raisin in jello
![Page 8: GSCI 163 Lecture 2. Atomic theory What are things made of? Imagine dividing an object into smaller and smaller units. Is there a limit to how much we.](https://reader035.fdocuments.in/reader035/viewer/2022070401/56649f165503460f94c2b875/html5/thumbnails/8.jpg)
Discovery of the nucleus
• Ernest Rutherford in 1907 found that the atom has a nucleus made of positive particles.
• 100,000 smaller than the orbit of the electron
![Page 9: GSCI 163 Lecture 2. Atomic theory What are things made of? Imagine dividing an object into smaller and smaller units. Is there a limit to how much we.](https://reader035.fdocuments.in/reader035/viewer/2022070401/56649f165503460f94c2b875/html5/thumbnails/9.jpg)
How is the nucleus held together?
• We need a glue to overcome electrical repulsion!
• New particle = neutron
• James Chadwick in 1932
![Page 10: GSCI 163 Lecture 2. Atomic theory What are things made of? Imagine dividing an object into smaller and smaller units. Is there a limit to how much we.](https://reader035.fdocuments.in/reader035/viewer/2022070401/56649f165503460f94c2b875/html5/thumbnails/10.jpg)
Dmitri Mendeleev
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Next class
Atomic states
• Read handout day 3• Quiz on these topics (first 10-15 min of class)