How to draw Lewis structure of molecules with N

[tinir]

Many times, I find it hard to draw correct Lewis structure of molecules with nitrogen. For instance: the Lewis structure of H2CNN. I thought it should be double bond between C and N and single bond between N and N, like this:

But actually it's not. I have done many problems like this wrong.

Please help me out! Thx!

 

[DrDu]

That's certainly a correct Lewis structure for this molecule. However, when viewed at as a representation of a valence bond structure, it may not be a structure with high importance.
The point is that the rightmost nitrogen has only a sextet. Transforming the lone pair of the central atom into a bond between the two nitrogens will lead to a structure fulfilling the octet rule on all atoms.

 

[tinir]

Thank you so much! It helps me a lot!

 

[Big-Daddy]

Could you give some more examples (just the molecular formula, not necessarily your attempts) of problems like this (since as you say you've tried several of them)? Because I originally did not get this one straight away and would love to work on a few more :)

 

[tinir]

OK, I will reply to you when I find those problems. I could not remember where exactly are they.