Atomic Model Timeline

Plato

440 BCE

Thecrizes that these solids froms of matter are composed of indivisble elements shaped like a triangle

Democritus

400 BCE

Introduced the idea of the atom as the basic building block, atoms were uniform, solid, hard, incompressible, and indestructible and that they moved in infinite numbers through empty space until stopped

The Alchemists

760

Laid the ground work for many chemical process, all metals were formed from two principles — mercury and sulfur.

Robert Boyle

1662

Robert Boyle Domonstracting that matter is made of tiny particles

Antone Lavoisier

1789

a series of experiments found that the total mass, defined that matter was composed of atoms that were not created or destroyed during chemical reactions.

John Dalton

1804

suggested that all matter was comprised of indivisble indestructible, All matter is composed of extremely small particles called atoms.

Amedeo Avogadro

1811

Made a hypothesis about equal values and volumes of the sea, equal volumes of gases at the same temperature and pressure contain the same number of molecules regardless of their chemical nature and physical properties.

Dmitri Mendeleev

1869

“elements arranged according to the value of their atomic weights present a clear periodicity of properties

Robert Millikan

1890

Presisly Determing the magnitude of the electrons charge

JJ Thompson

1897

J.J. Thomson's experiments with cathode ray tubes showed that all atoms contain tiny negatively charged subatomic particles or electrons.

Pierre And Marie Curie

1898

She suggested that the powerful rays, or energy, the polonium and radium gave off were actually particles from tiny atoms that were disintegrating inside the element

Albert Einstein

1905

mathematically predicted the size of both atoms of molecules, any liquid is made up of molecules

Ernest Rutherford

1911

Rutherford's atomic model became known as the nuclear model. In the nuclear atom, the protons and neutrons, which comprise nearly all of the mass of the atom, are located in the nucleus at the center of the atom.

Niels Bohr

1913

proposed a theory for the hydrogen atom, some physical quantities only take discrete values.

Henry G.J. Mosely

1913

arranged the elements in the periodic table according to atomic numbers

James Chadwich

1932

positively charged protons and neutral neutrons bound together as the atom's nucleus, with negatively charged electrons occupying energy levels surrounding the nucleus.