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Author Question: In drawing the Lewis structure for the dichromate ion, how many valence electrons does chromium have? (Read 1184 times)

sammy

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on: Sep 20, 2013
The periodic table says that Cr has only 1 valence electron but other sources say that when drawing a Lewis structure, it is considered to have 6 valence electrons. Why?


erika

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Reply #1 on: Sep 20, 2013
6 is correct. Cr2O7(-2) gives you 7 oxygens = -14 + (-2) = 12 divided by two Cr per anion = 6 for the formal valence of Cr in dichromate.


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theo

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Reply #2 on: Sep 20, 2013
The six valence electrons of chromium are the 4s2 and the 3d4. In this way, the chemistry of chromium is analogous to that of sulfur, 3s2 3p4.


sammy

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Reply #3 on: Sep 27, 2013
Marking this topic solved :D

Thanks so much for the help


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