Elements Table in History

  • 470

    Democritus - Greece

    Democritus	- Greece
    -extended his mentor, Leucippus’ atomic theory
    -formulated an atomic theory for the cosmos
    -the ideas that both his mentor and him are remarkably similar to modern-day science.
    -suggested that all matter is made of tiny particles which differ from each other in form, position, and arrangement
  • Isaac Newtown - England

    Isaac Newtown	- 	England
    -Theory of light
    -Suggested the planets orbiting path.
    -Three laws of motion -Proposed that atoms were held together by an attraction called force. Also suggesting that atoms were made up of small round spheres.
  • John Dalton - England

    John Dalton - England
    -all matter was made up of small particles called atoms.
    -each of the elements atoms are unique in size and weight.
    - Three types of atoms exist: simple (elements), compound (simple molecules), and complex (complex molecules). -Proposed an "atomic theory" with spherical solid atoms based upon measurable properties of mass.
    -found the approx. weight of atoms.
    -all elements are made of atoms.
  • George Johnstone Stoney - Ireland

    George Johnstone Stoney - Ireland
    -the Stoney scale
    -proposed the term electron
    -conception and calculation of an atom’s electric charge -Proposed that electricity was made of discrete negative particles he called electrons; introduced the idea of negative charge
  • Joseph John Thomson - England

    Joseph John Thomson - England
    -discovery of the electron and of isotopes
    -prove atoms had subatomic atoms
    -Plum Pudding model - allowed us to know about the existence of subatomic particles through cathode rays
  • Max Planck - Germany

    Max Planck	- Germany
    -quantum theory
    -created Planck’s constant
    -created Planck’s Law of Black-body Radiation The quantum theory was to be the foundation of our understanding of atomic and subatomic processes
  • Hantora Nagaoka - Japan

    Hantora Nagaoka	- Japan
    -Saturnian Model
    -Spectroscopy -even though the model created was incorrect it was based on the planetary positions and was a bases to the modern day model.
  • Robert Andrews Milikan - America

    Robert Andrews Milikan - America
    -measurement of the charge on the electron using the oil drop experiment
    -photoelectric effect -allowed us to measure the charge to mass ratio of an electron
  • Ernest Rutherford - New Zealand

    Ernest  Rutherford - New Zealand
    -discovered the concept of radioactive half life
    - proved that radioactivity involved the transmutation of one chemical element to another
    - differentiated and named alpha and beta radiation
    -created the Rutherford model of the atom which is which is a small positive charged and orbited by electrons
    -claimed that the nucleus was dense and positively charged.
    -claimed electrons were outside the nucleus
  • Henry Gwyn-Jeffreys Moseley - England

    Henry Gwyn-Jeffreys Moseley	- England
    -justification from physical laws of the previous empirical and chemical concept of the atomic number
    -arranged the periodic table by their atomic numbers
    -Moseley Law that is an empirical law concerning the characteristic x-rays that are emitted by atoms -After using Xray tubes to examine the atoms, he determined that the stomic number of an element is equal to the number of protons in the nucleus.
    -reorganised the perodic table so it was to be in the o
  • Niels Bohr - Denmark

    Niels Bohr	- Denmark
    -understanding of the structure of properties of atoms
    -the Bohr model of the atom’s shell which had atoms built up of successive orbital shells of electrons
    -the correspondence principle
    -the liquid drop model of the atomic nucleus -developed an explanation of atomic structure that underlies regularities of the periodic table of elements.
    - suggested that the outer orbits could hold more electrons than the inner ones, and that these outer orbits determine the atom's ch
  • James Chadwick - England

    James Chadwick - England
    -discovery of the neutron

    -Using alpha particles discovered a neutral atomic particle with a mass close to a proton. Thus was discovered the neutron.