History of Atomic Theory Project

Democritus

410

Democritus- Ancient Greek Philosopher
Democritus was born in 460 BCE and died on 370 BCE. He was a Greek philosopher, and he was the first person to create an Atomic Theory. His theory stated that all matter is made up of atoms. And that the atoms are the same in mass, size and shape.

Aristotle

420

Aristotles conrtibutionAristotle was born around 360 BC. Sometime around 340 BC he stated a theory that said everything was made up of 5 elements. Air, earth, water, fire, and aether which was a divine substance which made up the planents and stars.

Joseph Priestly

Oct 7, 1733

Historical outline of the Atomic TheoryJoseph Priestly was best known for his discovery of oxygen.

Antoine Lavoisier

Apr 10, 1743

Historical outline of the atomic theory
Antoine Lavoisier was on of the first people to make good use of balance. He suggested that the Combustion theory was based on sound mass measurments. He names oxygen. Also he proposed the Law of

John Dalton

Dec 30, 1776

Historical outline of the Atomic TheoryJohn Dalton made the Law of Multiple Proportions that lead directly to the atomic theory. He also made the sign for Water HO. Dalton also recognized the existence of atoms of elements and that compounds formed from the union of these atoms

J.J. Thompson

Oct 30, 1856

The Historical Outline of the Atomic TheoryThomson proposed the "plum pudding" model of the atom. In this model, the volume of the atom is composed primarily of the more massive (thus larger) positive portion (the plum pudding). The smaller electrons (actually, raisins in the plum pudding ) are dispersed throughout the positive mass to maintain charge neutrality.

Niels Bohr

Jun 1, 1871

Bohr's greatest contribution to modern physics was the atomic model. The Bohr model shows the atom as a small, positively charged nucleus surrounded by orbiting electrons. Bohr was the first to discover that electrons travel in separate orbits around the nucleus and that the number of electrons in the outer orbit determines the properties of an element.The chemical element bohrium (Bh), No. 107 on the Periodic Table of the Elements, is named for him.

Ernest Rutherford

Oct 30, 1871

Historical outline of the Atomic theoryProposed the idea of a nucleur atom based of a gold-foil experiment. Rutherfor proposed that all of the positive charge and all of the mass of the atome occupied a small space at the center of the atom and that most of the volume of the atom was empty space taken up by electrons.