( 1766 - 1844 )
By Courtney Finley and Sadye Thompson
John Dalton was an English chemist who established the modern day theory of the atom. He formulated the theory in order to explain chemical reactions.
Dalton was born in Eaglesfield, Cumberland, England on September 6th, 1766.
He died on July 27th, 1844 in Manchester, England.
- By 1805 Dalton had essentially produced an outline of his most important contributions, his two laws concerning the gaseous state and the atomic theory of matter. Dalton studied gases and discovered that elements combine with other elements to make compounds.
- Dalton’s theory had four primary postulates. First, he suggested that all elements are made up of tiny particles called atoms. Second, all atoms of the same element are identical. Atoms of different elements are different in some fundamental way. Third, chemical compounds are formed when atoms from different elements combine with each other. Finally, chemical reactions involve the reorganization of the way atoms are bound. Atoms themselves do not change.
- Dalton believed that the size of the atoms was the crucial determinant of an element's chemical properties. In 1803, Dalton published these results with his measurement of the relative weights of different gases, producing the first atomic weight table.
- Dalton viewed matter as composed of spherical particles and believed that these particles or atoms contained a shield of heat around them. This was essential for Dalton to explain why unlike particles tended to repel each other and thus produce a physical mixture of gases in the atmosphere.
- The ability of Dalton's atomic theory to explain the law of definite proportions was only the beginning of its impact on the field of chemistry. Another chemical problem that Dalton was able to solve using the atomic theory was the observation that a particular element such as nitrogen, for example, could combine with oxygen and form a series of unique compounds containing nitrogen and oxygen. This came to be known as the law of multiple proportions.
- Other interests of Dalton's included the study of color- blindness. To add further onto that, color-blindness was a condition that affected him.
- John Dalton was a Quaker.
- He was the second son of Joseph Dalton and Mary Greenup.
- On his death in 1844 more than 40,000 people filed past his coffin and a public funeral was held.
"John Dalton." Science and Its Times. Ed. Neil Schlager and Josh Lauer. Vol. 4: 1700 to 1799. Detroit: Gale, 2000. 186. Gale Virtual Reference Library. Web. 9 Oct. 2014.