Drawing the Lewis Structure of N20 (2E.13d)

[Jessa Maheras 4F]

I was having trouble discerning the Lewis structure for N20. Would someone be able to describe the process for drawing the structure? Thank you!

[madawy]

First, calculate the amount of electrons that the molecule should have:
N= 2 * (5) +
O= 6
=16

Thus, when you write N N O, giving each a single bond such that it is N--N--O and filling in the lone pairs so that each has a full valence, you get a total of 20 electrons. Thus, you need to add two more bonds somewhere. This is where formal charge comes in: you want the Oxygen to have the -1 since it is most electronegative, and the only way that works out is if there is a triple bond between the Nitrogens and a single bond with the oxygen. In the other resonance structures, the oxygen has a formal charge of +1 and 0 while a nitrogen is -1 or -2, which means it isnt the most stable.

[WUng_1D]

There are two lewis structures for N2O, the first one has N as the central atom and a triple bond connecting it to the other N molecule and a single bond connecting the oxygen molecule. As for the second lewis structure, N is the central atom again but there are double bonds connecting both the second N molecule and the O molecule.

[Jessica Booth 2F]

First, you count up all the valence electrons, 2(5) + 6= 16. Then you put the less electronegative atom in the middle, which is N. Then you arrange the O and other N symmetrically around the central O. Then you put the 16 electrons around the atoms. You find out that with just single bonds, not all the atoms have octets so there must be either double or triple bonds. N wants 3 bonds and 1 lone pair, so the nitrogens are triple bonded and the noncentral N has 1 lone pair to have an octet. This leaves a single O-N bond which makes sense because then oxygen has a formal charge of -1, which makes sense because O is more electronegative than N and you have used all your electrons.

[Jessica Chen 2C]

First we add up the valence electrons, and we find that we have 16 electrons to work with. We know N is the central atom because it has lower ionization energy than O. So we start off with N-N-O. We could use all the electrons to complete the octets for the outside N & O, but then we see that the central N's octet is incomplete, so we know we have to draw some double bonds. We can erase a lone pair from both the N and O, and replace it with double bonds (like N=N=O), and that would fulfill the octet rule for all the atoms. However, if we look at the formal charge, we see that the outer N is -1, central N is +1, and O is 0. Remembering that it's better for the negative charge to be on the most electronegative atom (O in this case), we realize this isn't the most stable Lewis structure. We can redraw it with a triple bond between the two N atoms, and a single bond between N and O, and that gives us formal charges of outer N: 0, central N: +1, and O: -1. This is a better Lewis structure for N2O.

[005384106]

This was very helpful in helping me determine when you make double bonds/ triple bonds/ single bonds.