Atom Timeline Scientists Contributions.

Timeline created by baytipping
  • John Dalton

    John Dalton
    John Daltons contribution to atoms is that he proposed the Atomic Theory. He said that atoms from elements can be distinguished by the diffrence in wheight. With this theory others started to investigate and experiment with the theory. He proposed diffrent ideas some of those where that elements are made of atoms. Also atoms can not be created or destroyed by chemical or physical process.
    "Dalton Atomic Theory." Dalton Atomic Theory. N.p., n.d. Web. 02 Sept. 2013.
  • John Dalton

    John Dalton
    John Daltons atomic model is composed by atoms that make up matter. Also that there is a way to organize there atoms that make up elements and that they should be disinguished by their weight.
  • John Dalton

    John Dalton
    Atom
  • William Crooke

    William Crooke
    He discovered Thallium and the cathode rays and their properties like they travel in straight lines. A cathode being "The elecroed or terminal by which current leaves a voltaic cell or battery."(Dictionary.com) This causes glass to look flouresent, they carry negative charge.
  • William Crooke

    William Crooke
    The cathode has positive and negative terminals. This can be compared to present time batteries and television. The rays travel in lines and they cause a glass glow.
  • J.J Thompson

    J.J Thompson
    J.J Thompson's contribution the the atomic theory was that he stated that atoms were composed of smaller particles just as cahode rays. These were called "corpuscles" or fractions of an atom, and they were 1000 times smaller that the atom. Eventually these corpucles were later refered to as electrons or negative charged particles.
  • J.J Thompson

    J.J Thompson
    He came up with the statement that a atom has negatively charged particles which are called electrons. He said that atoms celectrons almost equal to the atomic number. This was shown in the plum-pdding model of an atom. Negative charged atoms were spread in a cloud of positive charge. The plums would be negative inside the positive pudding, this is why it was named this way.
    "Plum Pudding Model." Universe Today RSS. N.p., n.d. Web. 03 Sept. 2013.
  • Ernest Rutherford

    Ernest Rutherford
    Opposite from J.J Thompson Ernest Rutherford discovered positively chargen particles now known as the proton. He also stated that atoms have a nucleus, this idea revolutionized all others. It was accomplished by preforming the Gold Foil Experiment. In the experiment he used alpha particles of projectiles and was able to reflect them backwards, it was done with Gold Foil. Also he He is also known for his creation and classification of rays Alpha and Beta, creating a categorization for gamma ray
  • Ernest Rutherford

    Ernest Rutherford
    This was the gold-foil experiment proving that the atom had a sort-of stucture. Using alpa particles he realized that positively charged particles are not spread out but located in one place, concentrated in the nucleus.
  • Niels Bohr

    Niels Bohr
    Niels Bohr suggested that the nucleus inside the atom was positively charged and negative chargeed particles were around it. The negative particles also known as electrons were known to only be able to travel in orbit. Also outer orbits could hold more electrons than inner ones.(known as the valance shell). When electrons jump from an outer orbit to an inner one they can send out radiation.
  • Niels Bohr

    Niels Bohr
    Negative charge was in orbit around the positive charged particles and the orbits have diffrent energy. These are called "shells". When energy is released by electrons it occupies a portion of the elctromagnetic spectrum or what we see as visible light. Electrons jump around in orbit.
  • Niels Bohr

    Niels Bohr
    The Quantum Mechanical Model. Quantum refers to "the smallest quantity of physical property, such as energy, that a system can possess according to the quantum theory" (dictionary.com) It identifies the energy level an electron is in and the number of orbitals.
  • James Chadwik

    James Chadwik
    James Chadwick, contributed to the atomic theory by stating the existance of neutrons. The neutrons were neutral because they did not hold positive or negative charge. The neutron is located in the nucleus of the atom, it increased the atoms mass but not the electrical charge.
  • James Chadwick

    James Chadwick
    James chadwick stated that there was neutros as part of the nucleus of an atom. The nuetros increased the amount of mass but not of charge.
    "Chadwick Atomic Model." Tutorvista.com. N.p., n.d. Web. 03 Sept. 2013.