atomic model; Strevell

Democritus

Nov 17, 1000

He believed matter consisted of extremely small particles that could not be divided. As a philosipher he came up with it by himself.

Aristotle

Nov 17, 1000

He thought there was not a limit to the number of times matter could be divided and as a philospher he also acme up with this theory on his own.

Antoine Lavoisier

Nov 17, 1789

Lavoisier had came up with the law of conservation of mass, which states that the total mass in a chemical reaction remains constant.

Joseph Louis Proust

Nov 17, 1799

His law states that if a compound is broken down into its constituent elements, then the masses of the constituents will always have the same proportions, even regardless of the how many or source of the original substance.

John Dalton

Nov 17, 1802

John studied gases in the air, he concluded that a gas consisted of individual particles. To figure this out he measured the masses of element when a compund is formed. In doing this he noticed no matter how large or small the sample, the ratio of the masses elements in the compound is always the same!

J.J Thomson

Nov 17, 1897

Thomson hypothesized that the beam was a stream of charged particles that caused the air to glow.By placing a positive plate and a negative plate on the opposites sides of each other and putting a sealed tube filled with gas at low pressure in between them, and then finally adding an electric current to it he found out that his hypothesis was right.

Ernest Rutherford

Nov 17, 1899

Rutherford discovered that uranium emite's fast moving particles have a positive charge.To find this out he did an experiment called " The Gold Foil Experiment" by following the flash of the beam he could observe the path of the alpha particle after it passed through the gold.

Hantaro Nagaoka

Nov 17, 1904

Hantaro suggested that an atom has a central nucleus. His model was based on an analogy of the stability of the Saturn rings. Using that analogy he figured that electrons move in orbits like the rings of Saturn.

Niels Bohr

Nov 17, 1915

Bohr focused on the electrons unlike Rutherford's experiment.Although he did agree with Rutherford's model in his model the electrons would move in sperical orbit at fixed distances from the nucleus.

Louis de Broglie

Nov 17, 1924

Broglie proposes that moving particles like electrons have some properties of waves. To find this their was no certain ways it says that within a few years evidence was collected to support this idea,

Erwin Schrodinger

Nov 17, 1926

Erwin develops a mathematical equation to describe the motion of electrons in atoms. His work leads him to developing the electron cloud model.

Walter Bothe

Nov 17, 1928

Bothe observed that beryllium emitted a highly penetrating, electrically neutral radiation when put together with alpha particles. Later on they discovered that this radiation could knock hydrogen atoms out of paraffin wax.Initially it was thought to be high-energy gamma radiation, since gamma radiation had a similar effect on electrons in metals.

James Chadwick

Nov 17, 1932

Chadwick confirms the existance of neutrons, which have no charge.But the atomic nuclei contains the neutrons and the postively charged protons.