Atomic Theory

  • 354

    Aristotle

    Aristotle
    -Believed of the four elements: air, water, earth, fire
    -Rejecte Democritus' ideas
    -Thought that you will always have a smaller piece of atom matter source
    http://cstl-csm.semo.edu/cwmcgowan/ch181/atomhist.htm
  • 400

    Democritus

    Democritus
    -used the word "atomos" for atom
    -father of the atom
    -believed all things consisted of tiny indivisual units source
    atomic theory notes slide 2
  • Robert Boyle

    Robert Boyle
    -Reintroduced the idea of the atom
    -Displaced the ideas by Aristotle
    -Called groups of atoms bodies
    -Supposed elements were ultimately composed of particles of various sorts and sizes, into which, they were not to be relsolved in any known way source
    http://www.crystalinks.com/boyle.html
  • Isaac Newton

    Isaac Newton
    -Proposed a mechanical universe with small solid masses in motion
    -Began to understand that atoms and or particles move and are not stationary source
    http://atomictimeline.net/index.php
  • Antoine Lavoisier

    Antoine Lavoisier
    -Proposed combustion theory (based on sound mass measurements)
    -Named Oxygen source
    http://cstl-csm.semo.edu/cwmcgowan/ch181/atomhist.htm
  • John Dalton

    John Dalton
    -Developd first atomic theory
    -Billiard Ball Model: each atom had a certain mass, size, and chemical behavior determined by element kind
    -Element consisted of atoms, all atoms of an element are identicle, each element is different (mass), chemical reaction involved the rearrangement of atoms source
    atomic structure notes slide 3-8
  • Joseph Gay-Lussac

    Joseph Gay-Lussac
    -Anouncd law of combining volumes
    -Showed that at thew same temperature and pressure two volumes of hydrogengas reacted with one volume of oxygen gas to produce two volumes of water sources
    http://cstl-csm.semo.edu/cwmcgowan/ch181/atomhist.htm
  • Amadeo Avogadro

    Amadeo Avogadro
    -Proposed molecular theory; two assumptions:
    1..Avogadro hypothesis- equal volume of gasses contains equal nuber of moecules at the same temperature and preassure
    2..gas molecules can divide during chemical reactions
    -Based on speculative assumptions
    -Lacked independent experimental evidence or theoretical evidence source
    http://www.chemistryexplained.com/Ar-Bo/Avogadro-Amedeo.html
  • Michael Faraday

    Michael Faraday
    -Discovered the relationship between electricity and magnetism (one could not exist without the other)
    -felt light was the motion or vibration of these lines of force source
    http://www.writework.com/essay/history-atomic-theory-and-michael-farraday-including-his-d
  • J. Plucker

    J. Plucker
    -built first functioning Cathode Ray
    -theorized that atomic particles contain a charge source
    http://www.preceden.com/timelines/65160-atomic-theory-timeline-project
  • Dimitri Mendeleev

    Dimitri Mendeleev
    -Developed first periodic table
    -Arranged by chamical properties
    -Listed elements in columns of increasing atomic mass, had many blank spaces for new elements Source
    http://cstl-csm.semo.edu/cwmcgowan/ch181/atomhist.htm
    http://creating.pbworks.com/w/page/16595568/Mendeleev%20and%20the%20periodic%20table
  • JJ Thomson

    JJ Thomson
    -Discovered electron using Cathode Ray Tube
    -tested several experiments each result was the same
    -Plum pudding model: most popular and widely accpted in that timw, atom had an internal structure source
    atomic structure notes slide 9-13
  • Marie Curie

    Marie Curie
    -discovered radioactive elements Polonium and Radium
    -studied uranium and thorium
    -called her spontaneous decay process "radioactivity" Sources
    http://atomictimeline.net/index.php
  • Phllip Lenard

    Phllip Lenard
    -correctly concluded that the majority of an atomsvolume is empty space
    -His model was composed of Dynamids: could account for atomic masses, internal structure, and the emptiness in the atom
    -Used the Aluminum Experiment-beam of electrons could pass
    through a sheet of Al foil source
    atomic structure notes slide 19-22
  • Hantaro Nagaoka

    Hantaro Nagaoka
    -first to present the atomic model close to the present day model
    -His model: was unstable and according to laws of planetary motion the atom will collapse over time, explained electrons moving around nucleus
    -atoms were able to give off electrons to form ions source
    atomic structure notes slide 23-26
    -explained different atomic weights
  • Richard Abegg

    Richard Abegg
    -Concluded that noble gasses are stable because of the 8 electrons in the outermost shel
    -proposed the valence bond theory
    -found that inert gasses have a stable "electron configuration" Sourse
    http://www.msnucleus.org/membership/html/jh/physical/atomictheory/lesson3/atomic3c.html
    http://www.barcodesinc.com/articles/timeline-on-atomic-structure.htm
  • Albert Einstein

    Albert Einstein
    -The quanta behaved like discrete particles which are called photon
    -atoms emit and absorb them
    -Albert wrote a paper that explained that light absorbtion can release electrons from atoms called "photoelectric effect" source
    http://www.nobeliefs.com/atom.htm
  • Robert Millikan

    Robert Millikan
    -Determined unit charge of electron with oil drop experiment
    -electron= 1.60 x 10^-19
    -Allowing for calculation of mass source
    http://creating.pbworks.com/w/page/16595568/Mendeleev%20and%20the%20periodic%20table
  • Ernest Rutherford

    Ernest Rutherford
    -Gold foil Experiement: proved atoms had a tiny, positivly charge center and atoms were mostly empty space
    -Discovered the nucleus
    -Nucleaus takes up majority of the atoms mass
    -Electrons move around the empty space surrounding nucleus source
    atomic structure notes slide 14-18
    atomic structure notes slide 14-18
  • Fredrick Soddy

    Fredrick Soddy
    -proposed that the same element exists in different forms
    -Theory of isotopes: different elements can be chemically indistinguishable but have different atomic weights
    -demonstrated how radioactive elements can disenigrate Source
    http://www.nndb.com/people/286/000099986/
  • Bohr

    Bohr
    -Student of Rutherford
    -electrons are placed in energy levels surrounding the nucleus
    -most extensive
    -explained how electrons could give off light source
    atomic structure notes slide 27-29
  • HGJ Mosely

    HGJ Mosely
    -discovered systematic relation between wavelength and atomic number
    -sorted chemical elements by their atomic number
    -developed early x-ray spectrometry equipement source
    http://www.famousscientists.org/henry-moseley/
  • Francis Anston

    Francis Anston
    -Invented mass spectograph
    -first to observe isotopes (three different hydrogen atoms) Source
    http://cstl-csm.semo.edu/cwmcgowan/ch181/atomhist.htm
  • Louis de Broglie

    Louis de Broglie
    -suggested electrons could act as both particles and waves
    -hypothesis confirmed in experimentthat showed electron beams could be diffracted or bent as they pass through a slit
  • Werner Heisenberg

    Werner Heisenberg
    -Heisenberg uncertainty principle: it is impossoble to know exactly both the velocity and position of a particle at the same time
    -we shouldn't view electrons as moving in well-defined orbits around the nucleus source
    http://www.howstuffworks.com/atom8.htm source
    http://www.howstuffworks.com/atom8.htm
  • Erwin Schrodinger

    Erwin Schrodinger
    -derived a set of wave functions for electrons
    -orbitals could be described as density clouds
    -densest area= greatest chance of finding an electron
    -least dense= lowest chance of finding an electron Source
    http://www.howstuffworks.com/atom8.htm
  • Paul Dirac

    Paul Dirac
    -predicted the existence of antiparticles and known for quantum mechanics
    -formulated quantum field theory Source
    http://www.famousscientists.org/paul-dirac/
  • James Chadwick

    James Chadwick
    -discovered neutron
    -nuclear fission of Beryllium and beta radiation released a neutron Source
    atomic structure notes slide 31
  • Glenn Seaborg

    Glenn Seaborg
    -discovered transuranium elements (6)
    -him and colleagues are responsible for the identification of more than 100 isotopes throughtout the periodic table
    -suggested a change om the layour of the periodic table Source
    http://www.nobelprize.org/nobel_prizes/chemistry/laureates/1951/seaborg-bio.html
  • Enrico Fermi

    Enrico Fermi
    -demonstrated that nuclear transformation occurs in almost every element subjected to neutron bombardment
    -conducted first controlled chain reaction releasing energy from the atom's nucleus source
    http://atomictimeline.net/index.php