Atomic Timeline

By JackB
  • 500 BCE

    Alchemists

    Alchemists wanted to create the fake philosophers stone to transmute base metals into the noble metals and to develop the elixir of life. Clearly these objectives were never fulfilled so they developed a structure of basic laboratory techniques and experimental methods some are still in use today.
  • 400 BCE

    Democritus

    Democritus thought that all matter consisted of invisible particles called atoms, he also knew that atoms cannot be destroyed, atoms are solid but invisible, atoms are homogenous, atoms come in different size, shapes, masses and positions. He figured that solids are made of small pointy atoms and liquids are made of large round atoms, and that oils are made of very fine small atoms.
  • 400 BCE

    Solid sphere model

    Democritus developed an indivisible, solid sphere model that said all matter is composed of indivisible tiny things that are so small they can not be seen through humans eyes.
  • 384 BCE

    Aristotle and fellow greeks

    Aristotle did not agree with Democritus and he thought that all matter was made up of the four elements ,Water, Fire, Earth and Air. Most of people agreed with Aristotle causing Democritus idea to be overlooked and forgotten about for 2000 years. Soon Aristotle’s idea was proven incorrect and his teachings are not taught in todays modern view of the atom.

  • John Dalton

    Dalton proposed the atomic theory, he inferred proportions of elements in compounds. He found the atomic weight and chemical symbols. He also had the most useful atomic theory of matter, he’s theory was created into his research into gasses

  • Daltons atomic theory

    Daltons atomic theory said that all matter was made up of atoms, indivisible and indestructible building of blocks, while all atoms were identical. Dalton theory also stated that all compounds were composed of combinations of these atoms in defined ratios. He also discovered that chemical reactions were a result of rearranging atoms

  • J.J Thomson

    Thomson discovered that electrons and subatomic particles when he was working with cathode ray tubes.

  • Plum Pudding model

    This model was discovered by Thomson. He said that the atom was sphere of positive electricity, which had negative particles throughout it. He named this the model of an atom/the plum pudding model

  • Max Planck

    Max came up with the original quantum theory, to come up with this, all he did was research from the previous scientists sand a little bit by himself, and then he wrote a book on the quantum theory, which was the behaviour of matter and energy in a atom. He was also looking at colour changes from energy, he also made a math equation to help with this theory.

  • Rutherfords experiment

    Rutherford used a thin foil made of gold to find positive and negative charges in an atom. He aimed a beam of alpha particles at a piece of gold foil that in accordance to the JJ Thomson model of an atom. Hough when they tested it, they found out that there was an empty space and a nucleus that contained the positively charged proton.

  • Ernest Rutherford

    Ernest ionised gas using radiation, and also found alpha and beta waves. He used his research and the magnetic properties of iron to find radio waves. He has also discovered the atomic nucleus using JJ Thompson’s research and findings.

  • Niels Bohr

    Bohr was the first to discover that electrons travel in seperate orbits around the nucleus and that the amount of electrons in the outer determines the properties of an element. When combines Rutherford description of the nucleus and Planck theory about quanta, Bohr explained what happens inside an atom and developed a photo of atomic structure. His work earned him a Nobel prize in 1922

  • The Bohr model

    Bohr proposed his quantised shell model of the atom to explain how electrons can have stable orbits around the nucleus, he modified the Rutherford model by requiring that electrons can have a stable orbit around the nucleus.

  • Electron cloud model

    This was discovered by Erwin schrodinger and Werner heisenberg. They came up with that an atom consists of a dense nucleus of many protons and neutrons. The nucleus is surround by electrons but all have a different energy level and different charges.

  • Planetary or solar system model

    Both Rutherford and Bohr contributed into this model. Rutherford said the atom is mostly empty space which has a nucleus and a positive charge surrounded by negative electrons, Bohr also stated that they circulate the atom

  • Louis de broglie

    He believed that electrons can act like particles and waves, the same as light. He also stated that the waves created by electrons contained in the orbit d the nucleus, set up standing waves of certain energy, frequency and wavelength, he had discovered that electrons can act like waves which helped explain some of the things electrons do that we had never been able to explain.

  • Erwin schrodinger

    He combined the equations for the Behavior of Wales with the de broglie equation to generate a model for the spread of electrons in an atom. The advantage of this model is it consists of math equations known as wave functions that satisfy the requirements placed on the behaviour of electrons.

  • Werner Heisenberg

    His uncertainty principal says that “it is impossible to measure simultaneously the exact position and exact velocity or momentum of sub-atomic particle like electron and neutron.

  • James chadwick

    James discovered the neutron in 1932 and he got awarded the Nobel prize for physics in 1935. He had also led the British team in the Manhattan project, in which the UK and Canada supported the USA’s world war 2 effort to build the worlds first nuclear bomb.