Atomic Timeline

  • 500 BCE

    The Alchemists

    The Alchemists
    There was a man in the Alchemists group named Aristotle. The idea that Aristotle had consisted of treating different metals to change the structure of the item, the item could become more valuable. Even though he failed to turn items into gold, he ended up making a scientific process which would help him discover the atom.
  • 460 BCE


    Democritus proposed that everything was is made up into tiny bits, but keep in mind that this was said a very long time ago, in 460 BCE. And as a "reference" to the Law of Conservation of Mass, Democritus said that atoms are indestructible.
  • 427 BCE


    Plato was the man who introduced the atomic theory in which absolute geometrical figures serve as atoms, according to which atoms broke down into triangles.
  • Robert Boyle

    Robert Boyle
    Robert Boyle was the inventor of Boyle's Law. He discovered that the volume of a gas decreases with increasing pressure and increases with decreasing pressure.
  • Antoine Lavoisier

    Antoine Lavoisier
    Antoine Lavoisier was a French scientist who contributed to the creation of the Atomic Theory. He went through a series of experiments to find that the total mass of products and reactants in a chemical reaction is always the same, and this is what led to the establishment of the Law of Conservation of Mass.
  • Billiard Ball Model

    Billiard Ball Model
    The Billiard Ball (Solid Sphere) Model was the first atomic model. It was developed by John Dalton and It shows that an atom is a solid sphere that cannot be broken up into smaller particles.
  • John Dalton

    John Dalton
    John Dalton was the first person to create the model of an atom. He proposed that all matter is made of tiny indivisible particles called atoms. He released a book in 1808 explaining that everything is made of atoms. He was a chemist who established the atomic theory.
  • Amadeo Avagadro

    Amadeo Avagadro
    Amadeo Avagadro was a scientist who was best known for his hypothesis that states that equal volumes of different gases contain an equal number of molecules. Also, he was the first scientist to discover that elements could exist in the form of molecules instead of individual forms.
  • JJ Thomson

    JJ Thomson
    JJ Thomson experimented with cathode ray tubes to show that all atoms contain tiny, negatively charged particles called electrons. He proposed the plum pudding model of the atom which showed the negatively charged electrons with a visual of the positively charged electrons.
  • Robert Millikan

    Robert Millikan
    Robert Millikan was a scientist who had an early major success of the accurate determination of the negative charge carried by an electron, using the "falling-drop method".
  • Dmitri Mendeleev

    Dmitri Mendeleev
    Dmitri Mendeleev was a man who was famous for discovering that all when all rhe known chemical elements are placed in oreder of increasing atomic weight, the endings displayed a recurring pattern, or periodicity within groups of elements.
  • Ernest Rutherford

    Ernest Rutherford
    Ernest Rutherford was a scientist known for his amazing studies of the atom. Evidence of his research consisted of how he found out that atoms mainly contain empty space, and the mass of it is mainly concentrated in the positively charged nucleus in the center. He also found that there are two radiation types, alpha and beta.
  • Albert Einstein

    Albert Einstein
    Albert Einstein was a physicist who contributed to the atomic theory by mathematically proving the existence of atoms, and furthermore revolutionized all the sciences through the usage of probability and statistics.
  • Niels Bohr

    Niels Bohr
    Niels Bohr was a young scientist who brought up a theory for hydrogen and the hydrogen atom. He is also the creator of the Bohr model. This theory was based on quantum theory that some physical quantities only take discrete values. He proposed that electrons cycle around the nucleus of an atom, but only in very specific orbits.
  • Erwin Schrodinger

    Erwin Schrodinger
    Schrodinger's model says that the electron is aware and tries to describe the regions in a space or orbitals, where electrons are most likely to be found.
  • Plum Pudding Model

    Plum Pudding Model
    The Plum Pudding Model was a model representing the atom. This model was first proposed by JJ Thompson in 1904. The model explained the two properties of atoms that electrons are negatively charged particles and that atoms have no net electric charge.
  • Marie and Pierre Curie

    Marie and Pierre Curie
    The Curie's discovered and isolated radium a new element which disintegrated into other elements. This proved that the atoms of one element at least were not indivisible.
  • Robert Millikan

    Robert Millikan
    Millikan viewed his cosmic ray photons as the "birth cries" of new atoms continually being created by god to interact entropy and prevent heat death. He was also Vice Chairman of the Nation Research Council during World War 1.
  • Solar System Model

    Solar System Model
    The Solar System Model demonstrates the relative positions and motions of the moons and planets in the Solar System.
  • Henry G.J. Moseley

    Henry G.J. Moseley
    Mosely was an English physicist who experimentally demonstrated that the major properties of an element are determined by the atomic number
  • Werner Heisenberg

    Werner Heisenberg
    Heisenberg formulated quantum mechanics in terms of matrices and discovered that a particles position and momentum cannot both be known exactly.
  • Electron Cloud Model

    Electron Cloud Model
    This model was made by Erwin Schrodinger and Werner Heisenberg. This model was made to visualize the most probable position of electrons in an atom.
  • James Chadwick

    James Chadwick
    James Chadwick was best known for his discovery of the neutron. A neutron is a particle that has no electric charge that, along with positively protons, makes up an atoms nucleus. this lead to Chadwick's discovery of the atomic bomb.