hpw would i draw a lewis structure for a molecule with 3.5 bonds

for example NO2???

http://www.madsci.org/posts/archives/2000-02/951452623.Ch.r.html

To draw a Lewis structure for a molecule with 3.5 bonds, such as NO2, we need to follow a series of steps:

Step 1: Determine the total number of valence electrons in the molecule. This can be done by adding up the valence electrons of each atom in the molecule. For NO2, the nitrogen (N) atom contributes 5 valence electrons, and each oxygen (O) atom contributes 6 valence electrons. Thus, the total number of valence electrons is 5 + 2(6) = 17.

Step 2: Identify the central atom in the molecule. The central atom is usually the one that is less electronegative than the other atoms. In this case, nitrogen (N) is the central atom.

Step 3: Use single bonds to connect the central atom to the surrounding atoms. In the case of NO2, nitrogen (N) is bonded to one oxygen (O) atom with a single bond.

Step 4: Distribute the remaining electrons around the atoms in the molecule, starting with the surrounding atoms first and then moving to the central atom. In the case of NO2, we have 17 valence electrons, and we have used 2 for the N-O single bond. This leaves us with 15 electrons.

Step 5: Fill the octet of each surrounding atom by placing remaining electrons as lone pairs. Oxygen (O) usually needs 6 electrons to complete its octet. In the case of NO2, we have used 6 electrons for one oxygen (O) atom. Therefore, we have 9 electrons remaining.

Step 6: Assign the remaining electrons to the central atom as lone pairs, with a maximum of 8 electrons (an octet). However, in the case of NO2, nitrogen (N) has only 5 electrons surrounding it so far. To increase the bonding, we can promote one lone pair from an oxygen (O) atom to form a double bond with nitrogen (N).

Step 7: Check if the central atom has an octet (8 electrons) and make adjustments if needed. In the case of NO2, nitrogen (N) now has 7 electrons surrounding it. To create a 3.5 bond, we can consider two possible resonance structures where the unpaired electron on nitrogen (N) is delocalized between nitrogen (N) and an oxygen (O) atom.

Thus, the Lewis structure for NO2 can be represented by a resonance structure where nitrogen (N) has one double bond and one single bond with the two oxygen (O) atoms and a lone pair on nitrogen (N).

N≡O:
|
O-N-O

I hope this helps in drawing the Lewis structure for a molecule with 3.5 bonds like NO2!