-
480 BCE
Leucipus (480 B.C.E.-5th century)
-Philosopher
-Developed the theory of atomism, later, Democritus adopted it.
-Master (teacher) of Democritus. -
460 BCE
Democritus (460 B.C.E.-370 B.C.E.)
-Studied natural philosophy and geometry.
-Adopted the atomic theory (The universe is composed by two elements, the atoms and the void in which they exist and move)
-Defined what atoms were.
-Created the first atomic model.
-His atomic model was simply a round sphere with no protons, electrons or neutrons. -
John Dalton (1766-1844)
-Chemist, scientist and meteorologist.
-One of the first pioneers of modern atomic theory.
-First scientist to explain the behavior of atoms in terms of the measurement of weight.
-Created another atomic theory consiting of: All matter was composed of atoms, While all atoms of an element were identical, different elements had atoms of differing size and mass. -
Eugen Goldstein (1850-1930)
-Physicist, investigator of discharge tubes
-Sometimes acredited with the discoveryr of the atom.
-Discovered canal rays, beams of positively charged ions.
-With his work, scientist could picture the atomic model more easily. -
J.J. Thompson (1856-1940)
-Studied mathematics and physics.
-Discovered electrons.
-Discovered that atoms could be divided.
-also, he concluded atoms are made of positive cores and negatively charged particles within it.
-Developed the Plum Pudding model, This model shows that the electrons are surrounded by a mass of positive charges to balance the negative charges. -
Ernest Rutherford (1871-1937)
-Physicist
-Created a new, updated atomic model, it added a nucleus, that held the protons and neutrons, outside, revolvng around the nucleus were the electrons, between the nucleus and electrons, there is void.
-Did many experiments with radioactivity. -
Niels Bohr (1885-1962)
-pioneered the atom structure
-Created a new model, not very different from Rutherford's.
-The idea of this new atomic model is to show how it worked, the nucleus lied in the center of the model and is made up of a certain number of protons and neutrons. Each of the outer layers is made up of a certain amount of electrons.
-The model limit to how many electrons can be in each electron shell is shown in the model. -
James Chadwick (1891-1974)
-Physicist
-Discovered the neutron.
-awarded the 1935 Nobel Prize in Physics for his discovery of the neutron in 1932.
-head of the British team that worked on the Manhattan Project during the Second World War. (Project working in the first atomic bomb)
