CHEM 1A Chapter Notes - Chapter 2: Cathode Ray Tube, Electric Field, Robert Andrews Millikan

• School: UC-Irvine
• Department: Chemistry
• Course: CHEM 1A
• Professor: Ramesh D Arasasingham

Document Summary

What are atoms: fundamental units from which all matter is built, very small, determine structure, behavior and properties of matter. History: idea dates back to fifth century, b. c. in greece, greek said that the all mater was composed of tiny particles, democritus argued that matter can"t be subdivided. Infinitesimally small piece of matter called atomos (uncuttable: 17th and 18th century, models are supported, not hypothetical. Argued that matter was composed of different particles. Discovered that substance can combine together or break apart go form new substances with different properties. Elements are material substances that could not be broken down further by chemical methods. Substances could combine with others to form new substances; other substances could be broken apart to form simpler ones. Atoms of different elements have different masses and properties: atoms of two or more different elements combine in simple whole number ratios to form compounds, atoms of one element cannot change into atoms of another element.