History of Atoms

Atoms and Elements

Atom- Smallest identifiable unit of an element and have no net electric charge. They are electrically Neutral

People of the Atom--Atomic Theory

• Democritus: Created the idea of the atom, and that they were indestructible
    * Was undermined because of Aristotle, which was the idea of matter being combination of fire, air, water, and earth
    * His ideas never explained the chemical behaviors
• John Dalton
    * Each element is composed of tiny, indestructible particles called ==Atoms==
    * All Atoms of a given element have the same mass and other particles that distinguish them from other elements and atoms
      * Isotopes
    * Atoms combine in simple. whole number ratios to form compounds
    * Atoms Cannot be subdivided (only by nuclear means)
    * In chemical reactions Atoms are combined, separated or rearranged

Laws

• Law of Definite Proportions: A chemical compound contains the same proportion by mass, regardless of the size of the sample
• Law of Multiple Proportions: When 1 Element combines with another to form more than 1 compound, the mass ratio of elements in the compounds are simple whole numbers of eachother