Scientist and their Contributions

Timeline created by fhschemistry
  • 460

    Democritus is born

    Democritus, a ancient greek philosopher was born in 460BC.
  • Dalton was born

    Dalton was a chemist who believed all matter is made of atoms.
  • Crook was born

    Crooke was a physicist and chemist who worked on spectroscopy and discovered the tube.
  • Mendeleev was born

    A Russian Chemist.
  • John Newlands was born

    A English chemist, one of the first to propound the conception of periodicity among the chemical elements.
  • Thompson discovers Cathode Rays

  • JJ Thompson is born

    Discovered Cathode Rays.
  • Crooke discovers thallium

    Crooke discovers new element Thallium.
  • John Newland publishes his law of octaves.

    ‘If the elements are arranged in order of their equivalents [ie relative atomic masses in today’s terminology] with a few transpositions, it will be seen that elements belonging to the same group appear in the same horizontal line. Also the numbers of similar elements differ by seven or multiples of seven. Members stand to each other in the same relation as the extremities of one or more octaves of music. T
  • Mendeleev wrote, "the Principles of Chemistry"

    Hendeleev wrote his book on the principles of chemistry 1868-1870.
  • Rutherford is born

    a Physicist and one of the nucleus founders.
  • Crooke discovers tube

    Crooke discovers tube
    Crooke discovers "Crookes Tube" in 1875.
  • Bohr was born

    A Danish physicist.
  • Niels Bohr:- Atomic Model

    Niels Bohr applies quantum theory to Rutherford's atomic structure by assuming that electrons travel in stationary orbits defined by their angular momentum. This led to the calculation of possible energy levels for these orbits and the postulation that the emission of light occurs when an electron moves into a lower energy orbit.
  • Aristotle is born

    Greek philosopher/scientist, born in 384BC.
  • Rutherford discovers the nucleus

    Atoms are electrically neutral in nature. A large heavy mass is present in the centre of an atom that have protons and neutral subatomic particles. Electrons are revolves around the nucleus in the fixed circular path known as orbit. This discovered atomic theory was largely accepted and gives a complete explanation of structure of an atom.
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