Here is a summary of Dalton's theory.
1. Elements are composed of tiny, separate, indivisible and indestructible particles. These particles, called atoms, maintain their identity when the element undergoes physical or chemical change.
2. All atoms of the same element are identical and different from the atoms of every other element.
3. Atoms combine in simple whole number ratios to form compounds.
4. Atoms of the same elements can combine in different ratios to form more than one compound.
A simple discussion of this theory and its background can be found here.
Berzelius, contributed significantly to the development of atomic theory. About 1807 he performed a great number of analyses of chemical compounds, and showed so many examples of the law of definite proportions that it could no longer be doubted. He also set about determining atomic weights and his first table, published in 1828, compared favourably with today's accepted values.
Whereas Dalton represented atoms of elements by circles containing a letter or symbol, Berzelius chose to omit the circle and just use an initial letter of the Latin name of the element (or two letters if more than one element began with the same letter). This led to the system we now use for writing formulae of elements and compounds and writing chemical equations.
Here is a summary of Dalton's theory.
1. Elements are composed of tiny, separate, indivisible and indestructible particles. These particles, called atoms, maintain their identity when the element undergoes physical or chemical change.
2. All atoms of the same element are identical and different from the atoms of every other element.
3. Atoms combine in simple whole number ratios to form compounds.
4. Atoms of the same elements can combine in different ratios to form more than one compound.
A simple discussion of this theory and its background can be found here.
Berzelius, contributed significantly to the development of atomic theory. About 1807 he performed a great number of analyses of chemical compounds, and showed so many examples of the law of definite proportions that it could no longer be doubted. He also set about determining atomic weights and his first table, published in 1828, compared favourably with today's accepted values.
Whereas Dalton represented atoms of elements by circles containing a letter or symbol, Berzelius chose to omit the circle and just use an initial letter of the Latin name of the element (or two letters if more than one element began with the same letter). This led to the system we now use for writing formulae of elements and compounds and writing chemical equations.
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