1 / 11

GSCI 163

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 can divide?. Atom. Means “ uncuttable ”. Democritus (460-362 BC). John Dalton (1766 – 1844). All matter is made of atoms

dino
Télécharger la présentation

GSCI 163

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. GSCI 163 Lecture 2

  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 can divide?

  3. Atom • Means “uncuttable”. Democritus (460-362 BC)

  4. 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.

  5. Is the atom indivisible? • J.J. Thompson – discovery of the electron 1897. The cathode ray tube

  6. What is the electron? • Robert A. Millikan in 1906 measured the charge of a single electron

  7. The model of the atom at this point • Positive and negative charges mixed like raisin in jello

  8. 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

  9. How is the nucleus held together? • We need a glue to overcome electrical repulsion! • New particle = neutron • James Chadwick in 1932

  10. Dmitri Mendeleev

  11. Next class Atomic states • Read handout day 3 • Quiz on these topics (first 10-15 min of class)

More Related