1 / 10

History of the Atom

History of the Atom. The Greeks (~2500yrs ago). Democritus a) 1 st idea of atom – smallest particle. Aristotle Observations, no experimentation All matter made up of 4 elements: Air, water, fire earth. 2. Antoine La Voisier 1743-1794. Discovered several elements.

ciara-conrad
Télécharger la présentation

History of the Atom

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. History of the Atom

  2. The Greeks (~2500yrs ago) • Democritus a) 1st idea of atom – smallest particle • Aristotle • Observations, no experimentation • All matter made up of 4 elements: • Air, water, fire earth

  3. 2. Antoine La Voisier1743-1794 • Discovered several elements b) Worked with law of conservation of mass c) Considered the Father of Modern Chemistry d) Beheaded during French Revolution

  4. 3. John Dalton(1766 - 1844) • Atomic Theory 1. Atoms are indivisible 2. All atoms of same element are identical BUT different than atoms of same element 3. Atoms combine in simple whole # ratios 4. Chemical rxns occur when atoms combine, split or rearrange

  5. 4. Thomson, Sir J.J. (1856-1940) • Cathode ray tube experiment (aka… raison bun or plum pudding model) • Set up a glass tube, free of air with magnets on each side • Sent a stream of particles thru it and observed which way they were deflected • Credited with discovery of electrons

  6. 5. Ernest Rutherford1871-1937 a) Gold Foil Experiment • Set up screen with thin Au foil in front • Shot stream of alpha particles (42He) thru • Most particles went straight thru, few deflected • Since 42He is + charge, once deflected, it’s off of something else + • Credited with discovery of nucleus with + charge due to protons

  7. 6. James Chadwick Discovered neutron 1. Same mass & location as proton

  8. Neils Bohr 1885-1962 • Solar system model of the atom • Electrons orbit nucleus in orbits called ENERGY LEVELS • Quantum – bundle of energy that an e- needs to change level • When e- change levels – not stable, they fall back towards nucleus & release energy in form of light that we see as colors (ROY G BIV)

  9. 8. Schrödinger • Quantum Mechanical Model 1. Deals with probability of where the electron is most likely located… Near the nucleus

More Related