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| | Chemical Valence (Site not responding. Last check: 2007-10-21) |
 | | The most likely formula for a chemical compound is when the number of atoms X the valence number [assume it to be positive] of that element, equals the number of atoms X the valence number [assume it to be negative] sum to zero, or the net charge on the compound, for example, (SO4)^ -2. |
 | | Although the concept of valence is firmly based on the quantum mechanics of atoms, in practice it is an empirical counting game that a student basically has to memorize the common valences associated with an element. |
 | | So Ca++ has a valence of +2, Cl- has a valence of -1, and they combine to form CaCl2, table salt, in which one positive valence of +2 and one negative valence of -1 sum to give a net charge of zero. |
| www.newton.dep.anl.gov /askasci/chem00/chem00039.htm (343 words) |
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