Lewis Structures and Valence Electrons?

[kLownn]

Hi there!

I was wondering if anyone could help me. With Lewis Structures and Valence electrons, do the valence electrons have to go in a certain order around the element symbol?
ie: four dots around each side of carbon, or two on the left side and two on the right side?

How would you do one like C₂H₅I?

One more question, how would one draw a lewis structure for a complex ion, like OH-?

Thanks! :)

 

[Renge Ishyo]

First place each electron one at a time (unpaired) on each of 4 sides of the chemical symbol. Only start pairing them up if you have an atom with more than 4 valence e's.

Hope this helped.

 

[Riogho]

No, it doesn't matter what order you have the electrons on the symbol, as long as you have the correct number. Of course, you could have a very anal teacher, in which case, do it how he wants it.

When drawing OH- what you would do of course, is bond the oxygen and the hydrogen with a single bond (hydrogen can never take more than a single bond) that counts as two of your 8 (it is 8 valence electrons because it is minus, if it was neutral than it would be 7 [6 valence electrons on the oxygen and 1 on the hydrogen]) electrons. Therefore you need to place 6 more electrons, and in this case, the only place to put them is around the oxygen, so you will draw 6 little dots around your O.

End.

 

[kLownn]

Thank you very much for your help! I can finish up my report now. :)
I am understanding these better~!