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History of the Atom

By vellaj
  • 360

    Aristotle

    Aristotle
    • Born 384 BC- Died 322 BC- He believed that all matter was made of just four elements: Earth, Water, Fire, Air.- He disbelieved the theory of other ancient greeks- He didn’t think atoms could move- He didn’t believe in atomic theory- He set back atomic theory a fair way, because people agreed with his thoughts. He was agreed with until the 17th century.
  • 460

    Democritus

    Democritus
    • Lived around 460 BC- First to call atoms ‘atoms’- Lived around 460 B.C- Proposed ultimate particle (atom)
    • First to determine that atoms are the smallest form of matter- - Gave us the first view of the possibility of atoms

  • Antoine Lavoisier

    Antoine Lavoisier
    • Born 26th August 1743, in Paris- Died 8th May 1794, by execution- Earned nickname of 'the father of modern chemistry'- He composed first element list- Named both Oxygen and Hydrogen
    • Proved that when combined they make Water (H20)- Discovered that matter cannot be destroyed via chemical reactions

  • John Dalton

    John Dalton
    • Born on 6th September, 1766- Died 27th July, 1844- Well known as a developer of atomic theory
    • Dalton’s atomic theory is the basis of many modern theories- Dalton believed that: •Elements are made of atoms (very small particles)•Atoms of one element are different from atoms of another•Atoms of an element are the same•Compounds are when atoms of an element combine with those of another•Atoms cannot be created or destroyed in a chemical reaction, only change

  • Joseph John Thomson

    Joseph John Thomson
    • Born 18th December, 1856- Died 30th August, 1940
    • Won Nobel Prize in 1906- Discovered that atoms were divisible and were made up of smaller particles- Created Plum Pudding Model, proving that atoms were divisible and were made up of smaller particles- He showed us that atoms are made of smaller parts- Discovered electrons and protons, but didn't know they were charged particles
    • Discovered that every atom both positive and negative particles

  • Ernest Rutherford

    Ernest Rutherford
    • Born August 30, 1871
    • Died October 19, 1937
    • Won Nobel Prize in 1908
    • Tested JJ Thomson’s theory and found that atoms are mostly empty space
    • Experiment included firing particles at atoms. He expected most to bounce off, but most went through, proving that the main mass of atoms sits in the middle.- The results of his testing gave Rutherford Nuclear Model
    • He proved that the main mass of an atom sits in the middle, and the rest is empty space

  • Henry Moseley

    Henry Moseley
    • Born November 23, 1887 - Died August 15, 1915 (in Gallipoli, WW1)- Created modern periodic table
    • Used atomic number as opposed to mass
    • This meant that elements were placed using protons as opposed to protons and neurons)

  • Max Planck

    Max Planck
    • Born April 23, 1858- Died October 4, 1947
    • Won Nobel Prize in 1918- He initiated quantum theory, which provided the base for quantum mechanics- Had the idea that energy didn’t flow constantly, it was broken into small packages (named quanta)

  • Frederick Soddy

    Frederick Soddy
    • Born September 2, 1877- Died September 22, 1956
    • Won Nobel Prize in 1921- Proposed idea of isotopes- Came up with theory that there can be different versions of one element with more neutrons but the same amount of protons.- Theory is known to be true- Also worked with radioactive materials

  • Niels Bohr

    Niels Bohr
    • Born October 7th,1885- Died November 18th, 1962
    • Won Nobel Prize in 1922 - Disproved previous theories that said atoms spiral into nucleus (like Rutherford's)- Created rules for atoms, including that atoms can only orbit at certain distances from nucleus (the more energy, the further away)-These are now known as electron shells. There is a limit to number of electrons that can be found on any shell. -The described it called the Bohr Model

  • Robert Andrews Millikan

    Robert Andrews Millikan
    • Born March 22, 1868- Died December, 1953
    • Won Noble Prize in 1923
    • He determined that electrons are negatively charged- Used oil-drop experiment to prove the charge

  • Louis de Broglie

    Louis de Broglie
    • Born August 15, 1892- Died March 19, 1987
    • Won Nobel Prize in 1929- He discovered wave nature of atomic particles and inspired Erwin Schrodinger- His theory helped to explain how atoms, molecules and protons behave

  • Werner Heisenberg

    Werner Heisenberg
    • Born December 5, 1901
    • Died February 1, 1976
    • Won Nobel Prize in 1932
    • Developed uncertainty principal which said that electrons don’t travel in neat electron shells- It also said that the location and energy of an electron can’t be determined at the same time, as it causes uncertainties- He used quantum mechanics to discover behaviour of atoms, electrons and subatomic particles

  • Erwin Schrodinger

    Erwin Schrodinger
    • Born August 12, 1887- Died January 4, 1961
    • Won Nobel Prize in 1933- He was inspired by de Broglie- Created an equation for wave mechanics which determines how electrons behave within an atom- His equation uses probability of where electron could be as opposed to definite position- Said that electrons were behaved as waves

  • James Chadwick

    James Chadwick
    • Born October 20, 1891- Died July 24, 1974
    • Won Nobel Prize in 1935- Chadwick discovered neutrons using Irene Joloit-Curie’s beam experiment- Discovered that the beam wasn’t deflected by positive or negative particles, and therefore there had to be neutral particles- After discovering neutrons, he added neutrons to atomic model