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This theory is based on the belief that during organic reactions there is a grouping of atoms that does not change. These groups of atoms, which have a kind of special stability, are called radicals. As an example, inorganic ammonium salts can be described using radical theory. Ammonium compounds are thought of as being combinations of the ammonia radical with elements or simple compounds.
| Ammonia radical : | NH3 | ||
| Ammonium chloride: | NH4Cl | = | NH3·HCl |
| Ammonium hydroxide: | NH4OH | = | NH3·H2O |
| Ammonium nitrate: | NH4NO3 | = | NH3·HNO3 |
This theory still is dualistic, but depends less heavily on the electrostatic attraction of oxides than the original theory of Dualism. Radical theory was developed by Liebig and Wöhler in the early 1830's. Although Berzelius was at first cool to the new theory, he later helped with its formulation.
Radicals are chemical groups that seem to have a special stability. We might think of them as the organic equivalent of the chemical elements. Examples of radicals are:
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There was general agreement that the radicals were fixed in composition, making it difficult for the radical theory to describe subsituted organic compounds. As we saw in the simulation, the small changes in properties that sometimes resulted from these substitutions led chemists such as Dumas to lay dualistic theories aside and to favor unitary theories, in which compounds are one whole. This eventually led to the concept of valence.
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Radicals are chemical groups that seem to have a special stability. We might think of them as the organic equivalent of the chemical elements. Examples of radicals are:
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In a substituted orgainic compound, other elements are substituted for a hydrogen. For instance, ethane reacts with chlorine to give chloroethane. CH3CH3 + Cl2 ---> CH3CH2Cl + HCl
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