CHEM 1F92 Chapter Notes - Chapter 2: Cathode Ray Tube, Cathode Ray, Subatomic Particle
Document Summary
In 500 bc, the greek philosopher democritus expressed his belief that all matter is composed of small, indivisible particles (which he called atomos). In 1808, john dalton generated an atomic theory which defined what we call atoms. The main ideas of his atomic theory are summarized below: elements are composed of tiny, indivisible particles called atoms, all atoms of a given element are identical (same size, mass, and chemical properties). However, the atoms of one element are different from atoms of other elements: compounds are composed of atoms of more than one element. In any compound, the ratio of the number of atoms of any two elements will be in whole numbers or fractions: a chemical reaction involves the separation, combination and rearrangement of atoms. Every molecule in carbon dioxide must have a 2:1 ratio of o atoms to c atoms.
