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Questions and Answers
Which scientist modified an earlier theory proposing that matter was made of four 'elements' (earth, fire, water, air)?
Which scientist modified an earlier theory proposing that matter was made of four 'elements' (earth, fire, water, air)?
Who was the first to adapt Democritus’ theory into the first modern atomic model?
Who was the first to adapt Democritus’ theory into the first modern atomic model?
Who was the first person to use the term 'atom' and propose the idea of indivisible particles?
Who was the first person to use the term 'atom' and propose the idea of indivisible particles?
Which scientist is credited for discovering the electron using cathode ray tube technology?
Which scientist is credited for discovering the electron using cathode ray tube technology?
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According to John Dalton's atomic model, what are atoms of different elements identical in?
According to John Dalton's atomic model, what are atoms of different elements identical in?
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Study Notes
Historical Theories of Matter
- Aristotle modified the earlier theory proposing that matter was composed of four elements: earth, fire, water, and air.
- He rejected Democritus' idea of indivisible particles, advocating for a qualitative understanding of matter in terms of these elements.
Development of Atomic Theory
- John Dalton adapted Democritus' atomistic theory into the first modern atomic model in the early 19th century.
- Dalton’s model emphasized that atoms were the primary building blocks of matter, explaining chemical reactions in terms of atomic combinations.
Concept of the Atom
- The term 'atom' was coined by Democritus, who proposed the idea of indivisible particles making up all matter.
- This was a significant departure from earlier concepts of matter as being continuous.
Discovery of Subatomic Particles
- J.J. Thomson is credited with discovering the electron through experiments with cathode ray tubes in 1897.
- His work revealed that atoms are composed of smaller, negatively charged particles, changing the understanding of atomic structure.
Dalton's Atomic Model
- According to Dalton’s atomic model, atoms of different elements are identical in mass and properties.
- This model proposed that each element's atoms are unique but comparable within their own types, laying the groundwork for the periodic table.
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Description
Test your knowledge of the history of atomic theory with this timeline quiz. Learn about the contributions of Democritus, Aristotle, and other key figures to the development of the atomic theory over the centuries.
