Modern Atomic Theory: includes the elements the compose atoms
5 Parts to his theory:
1. Elements are made of extremely small particles called atoms.
2. Atoms of a given element are identical in size, mass, and other properties; atoms of different elements differ in size, mass, and other properties.
3. Atoms cannot be subdivided, created, or destroyed.
4. Atoms of different elements combine in simple whole-number ratios to form chemical compounds.
5. In chemical reactions, atoms are combined, separated, or rearranged.
- Quaker in Cumberland England
- Was a teacher and public lecturer
- Moved to Manchester where he had more resources - so he pumped out his first paper about color blindness - called "Daltonism"
- Came to his view through meterology
- He kept daily weather records from 1787 until his death (first book was Meteorological Observations)
- Claimed that air was not a chemical solvent, but a mechanical system
- Law of partial pressures: The pressure exerted by each gas in a mixture is independent of the pressure exerted by other gases, and where the total pressure is the sum of the pressures of each gas.
- He proceeded to calculate atomic weights from percentage compositions of compounds, using an arbitrary system to determine the likely atomic structure of each compound.
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