Atomic Theory

Democritus (BCE)

450

Democritus descovered that everything is made up of atoms, they are physically, but not geometrically invisible. Between atoms is empty space. Atoms are indesturctable and will always be in motion. There is also an infinite amount of atoms and kinds of atoms which diifer in shape and size.

Dalton

Mar 13, 1803

Dalton changed Democirtus idea by saying compunds join atoms, all elements are composed of atoms, Atoms of different elements are different are different by their mass, and all atom of elements are exactly the same and have the same mass. Dalton also came up with a list of chemicals symbols and began to put them into a table. Also said all matters is made of atoms atoms are indivisble and indestructable.

Heisenberg and Schrodinger

Mar 13, 1887

Schrodinger discovered that rather than electrons being distributed within an electron configuration of shelld and energy levels, were arranged in orbitals which was systematically distributed within electron clouds. Orbital are the region of space that surrounds a nucleus in which two electrons may randomly move.
Heisnberg worked out that particles had a lot more energy over shot.

Thomson

Mar 13, 1897

J.J thomson identified the negatively charged electron in the cathode ray tube in 1897. He concluded that the electron was a component of all matter and calculaated the charge to mass ratio for the electron

Rutherford

Mar 13, 1909

Ernest Rutherford published his atommic theory describing the atom as having a central positive nucleus surrounding by negative orbiting electons

Bohr

Mar 13, 1913

Bohrs atomic theory states that the following rules govern the behaviour of electrons, electrons revolve in rits of specific radius around the nucleus; within each orbit, each electron has a fixed amount of energy; electrons in orbit farther away from the nucleus have greater energies to another of lower energy; an electron may absorb a proton radiation and jump from a lower-energy orbit to a higher-energy orbit.

Aristotle(BC)

Mar 2, 2022

Aristotle believed that all matters on Earth were made from four elements; not atoms. Therefore, he didn't believed in the atomic theory. The elements he had thought of were; Earth, waater, air, and fire, Aether was also an important element that Aristotle believed made up computers of planents and universe.