John Dalton

Background Born: in Cumberland, England Educated: in Quaker’s school in Eaglesfield Dalton had a teaching position in Manchester Best Known As: The weather pioneer who advocated atomic theory Died: 27 July 1844

Accomplishments Dalton discovered the partial pressure of gases John Dalton developed atomic theory; his theory (1805) accounts for the law of conservation of mass, law of definite proportions and law of multiple proportions; produced the first table of atomic weights; colorblind and mostly self-taught.

Dalton’s model of atom He believed that the atoms were tiny, indivisible, indestructible particles, and that each one had a certain mass, size, and chemical behavior that was determined by what kind of element they were.

Improvements for Dalton’s Model John Dalton’s model of the atom was improved in the sense that many more discoveries about the atom were made, and as time went on, technology improved so we were then able to see that the atom actually has more components that just what Dalton observed. Atoms actually have shells, sub-shells etc. In addition to a nucleus, protons, electrons, and neutrons. IMPROVED!

A Brief History of the Atomic Theory! 400 BC-350 BC Aristotle, Greece - started the method of gathering scientific facts, which began as the basis for all scientific work. John Dalton (1803), England - formed the atomic theory, which states that all matter is composed of tiny, indestructible particles called atoms that are all alike and have the same atomic weight. Albert Einstein (1905), Germany - stated that light was made up of different particles that, in addition to wavelike behavior, demonstrate certain properties unique to particles. He also brought forth the theory of relativity. Murray Gell-Mann and George Zweig (1964), USA - brought forth the idea of "quarks", little bits of matter which when used kind of like building blocks, serve to explain some complex chemical substances ** Only some, out of many stated (Most important ones).

Dalton’s Atomic Theory Up until Dalton’s time the atom was only considered to a philosophical construct passed down by the ancient Greeks. Dalton’s Theory: All matter is composed of atoms Atoms cannot be made or destroyed All atoms of the same element are identical Different elements have different types of atoms Chemical reactions occur when atoms are rearranged Compounds are formed from atoms of the constituent elements. **Dalton was mostly a theorist, and did not do any experiments!!

How theory fits with improvements It was noted that atoms can only be destroyed by only nuclear reactions not chemical reactions. Also there are different kinds of different masses, which are known as isotopes but still have the same chemical property as their element. we now know that atoms can be subdivided into protons, electrons, and neutrons. We'll get to that later though Dalton also imagined that in nature atoms always come in single groups, which we know is false too- most gases, like hydrogen and oxygen, are diatomic and are found in nature as a molecule of 2 atoms.

Works Cited "John Dalton." Chemical Heritage, Web. 7 Nov Francis, Eden. "Dalton's Atomic Theory." Web. 7 Nov Blamire, John. "History of Chemistry." Science at a Distance Web. 7 Nov < D. Leon, N. "Dalton's Atomic Theory." Web. 7 Nov < Jessa, Tega. "John Dalton's Atomic Model." 24 August Web. 7 Nov