1 / 16

Evolution of Atomic Theory: From Democritus to Dalton

Explore the historical progression of atomic theory, from Democritus and Aristotle to John Dalton. Learn about elemental substances, qualitative and quantitative data, laws of conservation, and Dalton's model of the atom.

kkarin
Download Presentation

Evolution of Atomic Theory: From Democritus to Dalton

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Development of theATOMIC THEORY

  2. Early Studies of Matter • The Greeks – more than 2000 years ago • Four Elemental Substances: • Fire, Earth, Wind, and Water Matter made up of particles...

  3. Democritus – 460 BC • Proposed that all matter is made up of indivisible particles that he called • Aristotle disagreed…so Democritus’ theory remain dormant until Dalton. ATOMS

  4. Democritus vs. Aristotle source source

  5. Robert Boyle - 1661 • Proposed that matter is composed of simple substances called elements that cannot be further decomposed or broken down. Qualitative Data

  6. Antoine Lavoiser - 1772 • Importance of • First stated Measurements Law of Conservation of Matter "Father of Modern Chemistry"

  7. Conservation of Mass H2 (g) + O2 (g)  H2O (l) 20 g + 160 g  180 g Mass is neither created nor destroyed!

  8. J. Proust – 1799 • In a pure compound, the elements combine in definite proportions to each other. Law of Definite Proportions

  9. Law of Definite Proportions decomposes H2O (l)  H2 (g) + O2 (g) 450 g  50 g + 400 g 90 g  10 g + 80 g When water decomposes the ratio of the mass of O2 to H2 is always 8:1

  10. Law of Multiple Proportions • Two elements can combine to form more than one compound ` • Ratio of the masses always a wholenumber! C + O  CO 1.00 g + 1.33 g  2.33 g C + O +O  CO2 1.00 g + 2.66 g  3.66 g 2:1

  11. John Dalton & Atomic Theory 1803 source Quantitative Data source

  12. Dalton’s Atomic Theory • Matter is composed of very small particles called atoms. • Atoms are indivisible and cannot be created or destroyed.* • All atoms of a given element are identical.* • Atoms of different elements are different. • Different atoms combine in whole numberratios to form compounds. • In chemical reactions, atoms are combined, separated or rearranged.

  13. Dalton’s Model of the Atom • Solid, indivisible sphere • Analogy: BILLARD BALL

  14. So Dalton’s atoms are kind of like billiard balls. Atoms combine in whole-number ratios.

  15. In a reaction, atoms are rearranged. + +  +

  16. So how big is an atom? • Most atoms are 1-2 angstroms across. • An angstrom = 1 X 10-10 m. • 6 Billion Copper atoms in a line -less than 1 meter!

More Related