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### Identifying the element

Posted: Mon Nov 05, 2018 11:36 pm
For the sixth edition chapter 3 #37, when given a lewis structure and asked to identify the element in the center, can we just explain our answer by saying that only an element with 5 valence electrons would make the formal charge 0, and the only element in period 3 with 5 valence electrons is Phosphorous?

### Re: Identifying the element

Posted: Mon Nov 05, 2018 11:38 pm
I believe that answer would suffice, especially since you brought in formal charge to explain your reasoning.

### Re: Identifying the element

Posted: Tue Nov 06, 2018 1:41 pm
Yes, mentioning stable structure and formal charge (how it equals to 0) would be the correct answer for the reasoning. If the formal charge doesn't equal 0, then it probably wouldn't be the correct element.

### Re: Identifying the element

Posted: Tue Nov 06, 2018 6:47 pm
Grace Kim 1E wrote:Yes, mentioning stable structure and formal charge (how it equals to 0) would be the correct answer for the reasoning. If the formal charge doesn't equal 0, then it probably wouldn't be the correct element.

I agree, I think as long as you support your answer scientifically with the formal charge and not just saying you can tell by looking at the periodic table then you should be good.

### Re: Identifying the element

Posted: Tue Nov 06, 2018 6:59 pm
Grace Kim 1E wrote:Yes, mentioning stable structure and formal charge (how it equals to 0) would be the correct answer for the reasoning. If the formal charge doesn't equal 0, then it probably wouldn't be the correct element.

I agree, I think as long as you support your answer scientifically with the formal charge and not just saying you can tell by looking at the periodic table then you should be good.

### Re: Identifying the element

Posted: Tue Nov 06, 2018 9:09 pm
Tagging on with the other posters formal charge is the explanation for the answer.

### Re: Identifying the element

Posted: Tue Nov 06, 2018 9:21 pm
Yes, I believe that answer would be fine. I also explained in mine how I was able to figure out that the element had 5 valence electrons by totaling the number of electrons in the lewis structure, and then subtracting the valence electrons of the other elements.

### Re: Identifying the element

Posted: Tue Nov 06, 2018 11:30 pm
Formal charge of the unknown atom, total electron numbers and how the unknown ion would add to that would be acceptable answers to this question I believe.

### Re: Identifying the element

Posted: Sat Nov 10, 2018 10:17 pm
For questions like these, are we always supposed to assume that the formal charge of the molecule is 0? Will the formal charge be provided when it is something other than 0?