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NO Lewis Structure

Nitric oxide (nitrogen monoxide) · A signalling molecule in the human body and a component of combustion exhaust.

Lewis structure of NO (Nitric oxide)The atoms around the centre are not all the same, so the bond dipoles are different sizes and cannot cancel.NO

The NO Lewis structure has 11 valence electrons, drawn as one N=O bond, with three lone pairs in total. The central N is sp2 hybridized and the molecule is linear. NO is polar: the atoms around the centre are not all the same, so the bond dipoles are different sizes and cannot cancel.

Odd number of valence electrons: this is a free radical, so one electron stays unpaired.

Calculated properties

Calculated properties of NO
Total valence electrons 11
Bonding electrons 4 (2 shared pairs)
Nonbonding electrons 7 (3 lone pairs + 1 unpaired electron)
Electron domains (steric number) 3
VSEPR notation AX1E2
Electron geometry trigonal planar
Molecular geometry linear
Bond angle no angle (only two atoms)
Hybridization sp2
Polarity polar
Formal charges all zero
Resonance structures none
Molar mass 30.006 g/mol

How to draw the NO Lewis structure

  1. Count the valence electrons

    Add up the outer-shell electrons every atom brings. That total is the budget for the whole structure - every line and every dot has to come out of it, and nothing may be added.

    5 (N) + 6 (O) = 11 valence electrons

  2. Work out what is bonded to what

    Two atoms, one connection. The only question is the bond order.

  3. Join everything with single bonds first

    Every connection starts as one shared pair. Draw them all before worrying about double bonds - the arithmetic in the next step is what tells you where the double bonds have to go.

    1 bond x 2 = 2 electrons used, 9 left

  4. Work out how far short you are

    Add up what every atom still needs to fill its shell - eight electrons for most atoms, two for hydrogen - minus what its single bonds already give it. Compare that with the electrons you have left. The difference decides everything that follows. This molecule has an odd electron count, so one atom has to settle for seven electrons rather than eight.

    needs 11, has 9, short by 2

  5. Turn the shortfall into multiple bonds

    Being short means atoms have to share more. Every pair that moves from a lone pair into a bond counts twice - once for each atom - so a shortfall of 2 is covered by 1 extra shared pair. That is where the double bond comes from.

    N=O

  6. Fill in the lone pairs

    Every electron not in a bond sits as a lone pair on an atom. Each atom takes exactly what it needs to finish its shell - there is no choice left at this point.

    N: 1, O: 2 (6 electrons)

  7. Check the formal charges

    Formal charge is valence electrons, minus lone-pair electrons, minus the number of bonds. Every atom here comes out at zero, which is the sign of a good structure.

    all formal charges = 0

  8. Work out the shape

    Count the electron domains on N: 1 bonded group plus 1 lone pair plus one unpaired electron. A double or triple bond still counts as one domain, because it points in one direction. That gives trigonal planar electron geometry; ignore the lone pairs and the atoms themselves sit in a linear arrangement. Two atoms can only lie in a straight line, so there is no bond angle to measure.

    steric number 3 -> sp2 -> linear

  9. Decide whether it is polar

    The atoms around the centre are not all the same, so the bond dipoles are different sizes and cannot cancel.

    dipoles do not cancel -> polar

Is NO polar or nonpolar?

NO is polar. The atoms around the centre are not all the same, so the bond dipoles are different sizes and cannot cancel.

BondElectronegativity differenceCharacter
N–O 0.40 polar covalent
Why this molecule gets set as a problem: Eleven valence electrons: a stable radical.

Common questions

How many valence electrons does NO have?

NO has 11 valence electrons. 4 of them are in bonds and 7 sit in lone pairs, with one electron left unpaired.

What is the molecular geometry of NO?

NO is a linear molecule. The central N has 1 bonded group and one lone pair, a steric number of 3, which gives trigonal planar electron geometry and a linear molecule.

What is the hybridization of NO?

The central N in NO is sp2 hybridized. Steric number 3 means 3 orbitals have to be mixed, which is exactly what sp2 gives you.

Is NO polar or nonpolar?

NO is polar. The atoms around the centre are not all the same, so the bond dipoles are different sizes and cannot cancel.

How this page was produced. The formula was parsed, the connectivity resolved (diatomic), and every bond-order arrangement enumerated and scored on octet satisfaction, formal charge and where that charge sits. The structure above is the winner. Bond angles, hybridization and the polarity verdict are read off the resulting geometry, not looked up.