-
360
Aristotle (c.360 BC)
Aristote disagreed with Democritus. People supported his theory that had no proof, because he was the teacher of Alexander the Great. He believed that all matter was made of the four elements (fire, air, water, and earth). His differing observations were based off of Democritus, but had no tangible evidence. He thought that the atom looked like one of the four elements that it was made of. -
360
Artistotle (c. 360 BC)
"Early Development of Atomic Theory." Early Development of Atomic Theory. N.p., 16 Apr. 2008. Web. 23 Feb. 2014.
Harvey, Nicole C. "Atoms and the Periodic Table." Zachary. 25 Feb. 2014. Lecture.
"HISTORICAL OUTLINE of the Atomic Theory and the Structure of the Atom." HISTORICAL OUTLINE of the Atomic Theory and the Structure of the Atom. N.p., n.d. Web. 22 Feb. 2014.
Walker, Jim. "History of Atoms." History of Atoms. N.p., Sept. 2004. Web. 24 Feb. 2014. -
460
Democritus (c. 460 BC)
Democritus discovered atoms when he wondered how many times matter could break before it could break anymore. He used theories and conducted experiments of splitting matter and used theories to conclude that the smallest particle of matter he called atoms. He thought that some atoms were round or jagged, which he believed affected the taste. -
460
Democritus (c. 460 BC)
Berryman, Sylvia. "Democritus." Stanford University. Stanford University, 15 Aug. 2004. Web. 24 Feb. 2014.
"Early Development of Atomic Theory." Early Development of Atomic Theory. N.p., 16 Apr. 2008. Web. 23 Feb. 2014.
Harvey, Nicole C. "Atoms and the Periodic Table." Zachary. 25 Feb. 2014. Lecture.
"HISTORICAL OUTLINE of the Atomic Theory and the Structure of the Atom." HISTORICAL OUTLINE of the Atomic Theory and the Structure of the Atom. N.p., n.d. Web. 22 Feb. 2014. -
Dalton
Bennett, Linda, T. "What Dalton Discovered." Dalton's Model. N.p., 2012. Web. 25 Feb. 2014.
"Early Development of Atomic Theory." Early Development of Atomic Theory. N.p., 16 Apr. 2008. Web. 23 Feb. 2014.
Harvey, Nicole C. "Atoms and the Periodic Table." Zachary. 25 Feb. 2014. Lecture.
Walker, Jim. "History of Atoms." History of Atoms. N.p., Sept. 2004. Web. 24 Feb. 2014. -
Dalton
- Atomic theory: agreed with Democritus that all atoms make up matter, invisible, and can't be broken down
- NEW: atoms of the same element have the same atomic mass, 2 different elements make a compound, atoms rearrange in a chemical reaction
- Evidence from experiments using chemical reactions show "lumpy particles"(atoms)
- works collected by Democritus
- model called "the billiard ball" - invisible atoms cannot be broken into smaller pieces
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Thomson
- discovered electrons and have a negative charge
- atoms have positive charge with negative parts too
- used Dalton's atomic theory to create his own
- used evidence that atoms are made of smaller pieces & not invisible
- "Plum Pudding model" atoms are spheres with a positive charge and negative electrons
-
Thomson
"Early Development of Atomic Theory." Early Development of Atomic Theory. N.p., 16 Apr. 2008. Web. 23 Feb. 2014.
Harvey, Nicole C. "Atoms and the Periodic Table." Zachary. 25 Feb. 2014. Lecture.
"HISTORICAL OUTLINE of the Atomic Theory and the Structure of the Atom." HISTORICAL OUTLINE of the Atomic Theory and the Structure of the Atom. N.p., n.d. Web. 22 Feb. 2014.Walker, Jim. "History of Atoms." History of Atoms. N.p., Sept. 2004. Web. 24 Feb. 2014. -
Rutherford
Rutherford discovered the nucleus that has a positive charge and where more than 99% of the atomic mass comes from, yet is extremely tiny. Discovered that electrons must orbit the nucleus. He made these discoveries though his Gold Foil Experiment: shot particles at gold foil to see that almost all particles passed through. His model of the atom was called "planetary model," because he said that the electrons orbit the nucleus like planets in the solar system. -
Rutherford
"Early Development of Atomic Theory." Early Development of Atomic Theory. N.p., 16 Apr. 2008. Web. 23 Feb. 2014.
Harvey, Nicole C. "Atoms and the Periodic Table." Zachary. 25 Feb. 2014. Lecture.
"HISTORICAL OUTLINE of the Atomic Theory and the Structure of the Atom." HISTORICAL OUTLINE of the Atomic Theory and the Structure of the Atom. N.p., n.d. Web. 22 Feb. 2014.
Walker, Jim. "History of Atoms." History of Atoms. N.p., Sept. 2004. Web. 24 Feb. 2014. -
Bohr
Walker, Jim. "History of Atoms." History of Atoms. N.p., Sept. 2004. Web. 24 Feb. 2014.
"HISTORICAL OUTLINE of the Atomic Theory and the Structure of the Atom." HISTORICAL OUTLINE of the Atomic Theory and the Structure of the Atom. N.p., n.d. Web. 22 Feb. 2014.
Harvey, Nicole C. "Atoms and the Periodic Table." Zachary. 25 Feb. 2014. Lecture.
"Early Development of Atomic Theory." Early Development of Atomic Theory. N.p., 16 Apr. 2008. Web. 23 Feb. 2014. -
Bohr
Bohr said that electrons do not spiral into the nucleus,but they
1. orbit a distance away from the nucleus
2. atoms radiate energy when electrons move energy levels
3. atoms absorb more energy when e- move from low to high energy levels
He refined Rutherford's theory and made observations about the electron to create his own theory. Bohr thought the atom had a positive nucleus with different energy levels where only certain numbers of electrons can exists- called "Bohr model" -
Heisenberg & Schrodinger
"Early Development of Atomic Theory." Early Development of Atomic Theory. N.p., 16 Apr. 2008. Web. 23 Feb. 2014.
Harvey, Nicole C. "Atoms and the Periodic Table." Zachary. 25 Feb. 2014. Lecture.
"HISTORICAL OUTLINE of the Atomic Theory and the Structure of the Atom." HISTORICAL OUTLINE of the Atomic Theory and the Structure of the Atom. N.p., n.d. Web. 22 Feb. 2014.
Walker, Jim. "History of Atoms." History of Atoms. N.p., Sept. 2004. Web. 24 Feb. 2014. -
Heisenberg and Schrodinger
- developed the electron cloud,caused by fast moving electrons
- there aren't orbitals, but electrons andomly move around the electron cloud -Schrodinger: used other physicist's hypotheses and Heisenburg's Uncertainly Principle
- Schrodinger= "atom wave model" or "quantum mechanical model"
- Heisenberg-uncertainty principle- can't know both the speed and location at the same time of an electron
- thought there weren't orbitals, and electrons moved in wave like patterns in the electron cloud
