History of Atomic Structure

Democritus

460 BCE

Democritus thought of the idea that everything in the universe was made up of invisible, indestructible atoms.

John Dalton

1766

Dalton's atomic theory consisted of three parts, all matter is made out of atoms, atoms are invisible and indestructible, and compounds are made of two or more atoms.

Dmitri Mendeleev

1834

Mendeleev was credited with creating the first periodic table in which he arranged the elements by their atomic mass.

Eugene Goldstein

1850

Goldstein was the first person to discover the proton by observing rays going from the from the cathode to electrons.

J.J Thomson

1856

Thomson discover the electron and developed the atomic theory.

Max Planck

1858

Planck is known as the creator of the quantum theory and contributed to the understanding of subatomic processes.

Robert Millikan

1868

Millikan determined the size of the charge in an electron through his famous oil drop experiment.

Ernest Rutherford

1871

Rutherford was the first to discover that atoms have a charged nucleus surrounded by empty space and circled by tiny electrons.

Niels Bohr

1885

Bohr found out that electrons travel in seperate orbits around the nucleus and that the amount of electrons determines the properties of the element.

Erwin Schrodinger

1887

Schrodinger came up with the Electron Cloud Method which consisted of a nucleus surrounded by a cloud of electrons

James Chadwick

1891

Chadwick discovered the neutron in the atom which is in the middle of the atom and doesn't have a positive or negative charge.

Werner Heisenberg

1901

Heisenberg is known for his theory of quantum mechanics.