John Dalton: Difference between revisions
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'''John Dalton''' (1766-1844) was an [[English people|English]] scientist. He taught [[mathematics]] and [[physical sciences]] at New College, Manchester. Dalton revived the atomic theory of [[matter]], which he applied to a table of atomic weights and used in developing his law of partial pressures ([[Dalton's law]]). He was [[color-blind]] and studied that affliction, also known as Daltonism. | '''John Dalton''' (1766-1844) was an [[English people|English]] scientist.<ref name=brit>[http://www.britannica.com/EBchecked/topic/150287/John-Dalton John Dalton. Free full-text article from Encyclopedia Britannica.]</ref> He taught [[mathematics]] and [[physical sciences]] at New College, Manchester. Dalton revived the atomic theory of [[matter]], which he applied to a table of atomic weights and used in developing his law of partial pressures ([[Dalton's law]]). He was [[color-blind]] and studied that affliction, also known as Daltonism. | ||
Another important achievement of Dalton's was his law of ''multiple proportions'': If two [[elements]] form more than one compound, the weights in different compounds of an element are ratios of integral numbers. For instance, consider the elements [[nitrogen]] and [[oxygen]]. The element oxygen occurs in the compounds NO and NO<sub>2</sub>. The ratio of oxygen weights (1:2) in these compounds contains the integral numbers 1 and 2. (Note that in modern chemistry the concept "weight", used by Dalton, is replaced by "number of atoms". Now we say that the ratio of numbers of O-atoms in different NO<sub>x</sub> compounds is a [[rational number]]. Or, by extension of Dalton's law of multiple proportions, the subscripts m, n, k, ... in a compound A<sub>m</sub>B<sub>n</sub>C<sub>k</sub>⋅⋅⋅ are integral numbers.) This law led Dalton to take the mass of the lightest element, [[hydrogen]], as unit of [[atomic mass]]. | Another important achievement of Dalton's was his law of ''multiple proportions'': If two [[elements]] form more than one compound, the weights in different compounds of an element are ratios of integral numbers. For instance, consider the elements [[nitrogen]] and [[oxygen]]. The element oxygen occurs in the compounds NO and NO<sub>2</sub>. The ratio of oxygen weights (1:2) in these compounds contains the integral numbers 1 and 2. (Note that in modern chemistry the concept "weight", used by Dalton, is replaced by "number of atoms". Now we say that the ratio of numbers of O-atoms in different NO<sub>x</sub> compounds is a [[rational number]]. Or, by extension of Dalton's law of multiple proportions, the subscripts m, n, k, ... in a compound A<sub>m</sub>B<sub>n</sub>C<sub>k</sub>⋅⋅⋅ are integral numbers.) This law led Dalton to take the mass of the lightest element, [[hydrogen]], as unit of [[atomic mass]]. | ||
==References and notes cited in text== | |||
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Revision as of 21:34, 6 September 2008
John Dalton (1766-1844) was an English scientist.[1] He taught mathematics and physical sciences at New College, Manchester. Dalton revived the atomic theory of matter, which he applied to a table of atomic weights and used in developing his law of partial pressures (Dalton's law). He was color-blind and studied that affliction, also known as Daltonism.
Another important achievement of Dalton's was his law of multiple proportions: If two elements form more than one compound, the weights in different compounds of an element are ratios of integral numbers. For instance, consider the elements nitrogen and oxygen. The element oxygen occurs in the compounds NO and NO2. The ratio of oxygen weights (1:2) in these compounds contains the integral numbers 1 and 2. (Note that in modern chemistry the concept "weight", used by Dalton, is replaced by "number of atoms". Now we say that the ratio of numbers of O-atoms in different NOx compounds is a rational number. Or, by extension of Dalton's law of multiple proportions, the subscripts m, n, k, ... in a compound AmBnCk⋅⋅⋅ are integral numbers.) This law led Dalton to take the mass of the lightest element, hydrogen, as unit of atomic mass.
References and notes cited in text
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Many citations to articles listed here include links to full-text — in font-color blue. Accessing full-text may require personal or institutional subscription to the source. Nevertheless, many do offer free full-text, and if not, usually offer text or links that show the abstracts of the articles. Links to books variously may open to full-text, or to the publishers' description of the book with or without downloadable selected chapters, reviews, and table of contents. Books with links to Google Books often offer extensive previews of the books' text. |