Which Atom Holds the Unpaired Electron in Nitric Oxide's Lewis Structure?

In summary, the NO molecule has a total of 11 electrons, with a double bond between the Nitrogen and Oxygen atoms. The Lewis structure can have two variants, with either the unpaired electron on the Nitrogen or Oxygen atom. The "formal charge" rule states that it is preferable for the atoms to have the same number of electrons around them after bonding, and the placement of the unpaired electron depends on this rule. The Lewis structure for NO should have a neutral octet and ensure charge neutrality on both atoms for maximum stability.
  • #1
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Take Nitric Oxide for example. When I've drawn out the Lewis structure, how do I know whether the unpaired electron belongs in the nitrogen or the oxygen? Are both variants of the NO Lewis structure acceptable? Furthermore, if both of these variants are accepted, is there a "resonance" of NO in which the extra unpaired electron is delocalized between the two atoms?
 
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  • #2
An Oxygen atom has 6 valance shell electrons and a Nitrogen atom has 5 valance shell electrons for a total of 11 electrons in the NO molecule.
The Lewis structure of the molecule has a double bond between the Nitrogen and the Oxygen atom, but in order to figure out how many lone pairs and unbonded single electrons I believe this is a situation where one would use the "formal charge" rule (is that the name of it?).

It is "preferable" for the atoms to "see" the same number of electrons around them after the bonds are made as they originally had (for a formal charge of zero), if they "see" too many, they have a negative formal charge, if not enough, then a positive formal charge. By "see" I mean to say the total of their unbonded electrons + 1 electron for every bond that was made.

So if you get to the point of the Lewis structure where you have a double bond between N and O and then have placed two lone pairs around the Oxygen and 1 long pair around the Nitrogen...where to place that last electron?
As it is, Oxygen would have a formal charge of zero since it has 2 lone pairs and a 2 bonds. Nitrogen gas a formal charge of +1 since it has two bonds plus 1 long pair. By placing the unbonded electron around Nitrogen you change its formal charge back to zero and complete the Lewis structure.

NO Lewis structure:
http://upload.wikimedia.org/wikipedia/en/9/9a/Nitricoxide.png
 
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  • #3
Oh yeah, forgot about that. Thanks.
 
  • #4
There's this rule of thumb that you can keep handy for drawing up Lewis structures.

From greatest stability to least: neutral octets > charged octets > neutral non-octets > charge non-octets

In the case of NO, you can not have two octets. The best you can do is have one octet and ensure charge neutrality on both atoms.
 

Related to Which Atom Holds the Unpaired Electron in Nitric Oxide's Lewis Structure?

What are molecules with odd electrons?

Molecules with odd electrons are molecules that have an odd number of valence electrons. This means that they have an unpaired electron in their outermost energy level.

How are molecules with odd electrons different from other molecules?

Molecules with even numbers of electrons tend to be more chemically stable because their electrons can pair up. Molecules with odd electrons, on the other hand, are often more reactive and can participate in chemical reactions more easily.

What are the properties of molecules with odd electrons?

Molecules with odd electrons can have unique magnetic properties due to their unpaired electron. They can also have different shapes and bond angles compared to molecules with even electrons.

What are some examples of molecules with odd electrons?

Some examples of molecules with odd electrons include nitrogen oxide (NO), nitric oxide (NO2), and chlorine monoxide (ClO).

How are molecules with odd electrons studied in chemistry?

Molecules with odd electrons are often studied using spectroscopy techniques, such as electron spin resonance (ESR). These techniques allow scientists to observe the behavior of the unpaired electron and understand the electronic structure of the molecule.

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