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Identifying elements in Lewis structures

Posted: Mon May 14, 2018 11:17 pm
by Toru Fiberesima 1L
For question 3.37, why would the answer be phosphorus specifically and not, say nitrogen, or any of the other period 3 elements. Would they not all work due to having 5 valence electrons. In general, how does one figure out an unknown element from a lewis structure?

Re: Identifying elements in Lewis structures  [ENDORSED]

Posted: Tue May 15, 2018 9:18 am
by Luis Avalos 1D
It specifically says "period 3 element" which is Na through Ar, and nitrogen is a period 2 element. On top of this, the central atom does not strictly follow the octet rule which is also an indication that it would not be nitrogen.

Re: Identifying elements in Lewis structures

Posted: Tue May 15, 2018 11:24 pm
by nicolesalcedo
Lavelle hasn't gone over this so I'm not 100% certain, but I would use the charges of the known elements in the lewis structure, count the number of shared electrons/bonds the central element has, and count the total number of electrons the lewis structure contains. I think all of these would help specify the unknown element.