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The History of Atomic Theory. 2. Cartoon of the day…. Today’s Warm-up. Warm-up: Black-box With your lab group of 4, investigate and predict (w/out opening) what is in your “black box” How did you come to that conclusion? What senses did you use? Did you use any tools?
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Today’s Warm-up • Warm-up:Black-box • With your lab group of 4, investigate and predict (w/out opening) what is in your “black box” • How did you come to that conclusion? • What senses did you use? • Did you use any tools? • Can you think of any tools that would make your prediction more likely or accurate?
Atomic Theory: History & Models Questions Vocabulary words Formulas Main Ideas Possible Test Questions Key Concepts Notes Notes Notes Notes Notes Notes Notes Notes Notes Notes Summary of the notes and information learned
Today’s Research • Famous scientists who contributed to the atomic theory/atomic model (not in any order): • John Dalton • Aristotle and Democritus • alchemists • J.J. Thompson • electron cloud model • Niels Bohr • Earnest Rutherford
Atomic Structure Timeline Requirements: (work in lab groups of 4) • Must include a title. • Must include a spot for each of the 7 items. • Must include at least the Who, When, and What. • Must have a picture/drawing (color is preferred) for each item. Options: • Comic book format • Standard timeline • PowerPoint slideshow • Other??? History of Atomic Structure History of the Atomic Model
Ancient Philosophy • Who:Aristotle, Democritus • When: More than 2000 years ago • Where: Greece • What: Aristotle believed in 4 elements: Earth, Air, Fire, and Water. Democritus believed that matter was made of small particles he named “atoms”. • Why: Aristotle and Democritus used observation and inference to explain the existence of everything.
Democritus Aristotle
Alchemists • Who:European Scientists • When: 800 – 900 years ago • Where: Europe • What: Their work developed into what is now modern chemistry. • Why: Trying to change ordinary materials into gold.
Atomic Particle Theory • Who:John Dalton • When: 1808 • Where: England • What: Described atoms as tiny particles that could not be divided. Thought each element was made of its own kind of atom. Developed the “Atomic Theory” • Why: Building on the ideas of Democritus in ancient Greece.
Dalton’s Atomic Theory • 1:Elements are composed of small indivisible particles (atoms) • 2: Atoms of the same element are identical. Atoms of different elements are different. • 3: Atoms of different elements combine together in simple proportions to create compounds. • 4: In a chemical reaction, atoms are rearranged, but not changed.
Discovery of Electrons • Who:J. J. Thompson • When: 1897 • Where: England • What: Thompson discovered that electrons were smaller particles of an atom and were negatively charged. • Why:Thompson knew atoms were neutrally charged, but couldn’t find the positive particle.
Atomic Structure I • Who: Ernest Rutherford • When: 1911 • Where: England • What: Conducted an experiment to isolate the positive particles in an atom. Decided that the atoms were mostly empty space, but had a dense central core. (gold foil exp.) • Why: He knew that atoms had positive and negative particles, but could not decide how they were arranged.
Atomic Structure II • Who: Niels Bohr • When: 1913 • Where: England • What: Proposed that electrons traveled in fixed paths around the nucleus. Scientists still use the Bohr model to show the number of electrons in each orbit around the nucleus. • Why: Bohr was trying to show why the negative electrons were not sucked into the nucleus of the atom.
Electron Cloud Model • Electrons travel around the nucleus in random orbits. • Scientists cannot predict where they will be at any given moment. • Electrons travel so fast, they appear to form a “cloud” around the nucleus.
Atomic Structure Timeline Requirements: • Must include a title. • Must include a spot for each of the 7 items. • Must include at least the Who, When, and What. • Must have a picture (color is preferred) for each item. Options: • Comic book format • Standard timeline • PowerPoint slideshow • Other???
Atomic Theory: History & Models Questions Vocabulary words Formulas Main Ideas Possible Test Questions Notes Notes Notes Notes Notes Notes Notes Notes Notes Notes Summary of the notes and information learned