The Atom: From Philosophical Idea to Scientific Method

The Atom: From Philosophical Idea to Scientific Method

1. Basic Laws

   • Law of Definite Proportions: A compound contains the same elements in exactly the proportions by mass regardless of the size of the sample of the compoun.
   • Law of Multiple Proportions: If two or more different compounds are composed of the same two elements, then the ratio of the masses of the second element combined with a certain mass of the first element is always a ratio of small whole numbers.
   • Law of Conservation of Mass: States matter cannot be created nor destroyed during ordinary chemical reactions and physical changes.

2. Atoms

   • Atoms of an element are identical in size, mass, and other properties.
   • Atoms of different elemnts differ in size, mass, and other properties.
   • Atoms cannot be subdivided, created, or destroyed.
   • Atoms of different elements combine in simple whole-number ratios to form chemical compounds.

3. Elements

   • A substance that cannot be further broken down by ordinary chemical means.
   • Two elements sometimes combine to form more than one compound
   • Are composed of atoms.

4. Chemicals

   • Reactions
     • - The combination of substances to form new ones. - Atoms are combined, separated, or rearranged.
   • Regardless of where or how pure chempical compouds is prepared, it is composed of a fixed proportions of elements.

5. Matter

   • All matter is composed of atoms.