Q 1-1-26E - Organic Chemistry (Mcmurry)

Question

Draw an electron-dot structure for acetonitrile, , which contains a carbon-nitrogen triple bond. How many electrons does the nitrogen atom have in its outer shell? How many are bonding, and how many are nonbonding?

Step-by-Step Solution

Answer

Nitrogen has five valence electrons in its outer shell. Of which three are bonding and two are nonbonding electrons

                           Electron dot structure of acetonitrile

Bonding and nonbonding electrons in acetonitrile

Valency of carbon, hydrogen, and nitrogen

Hydrogen has one valence electron, carbon has four valence electrons, and nitrogen has five valence electrons. Thus, the electron dot structure for acetonitrile is represented as:

           Electron dot structure of acetonitrile

Bonding and non-bonding electrons

Valence electrons that are not used for bonding are called lone pair electrons, or nonbonding electrons. Nitrogen has five valence shell electrons 1s²2s²2p³in its outer shell.

The nitrogen atom in acetonitrile, C₂H₃N for instance, shares six valence electrons in a triple bond and has its remaining two valence electrons in a nonbonding lone pair.

Nitrogen has five valence electrons in its outer shell. Of these five electrons, three are bonding electrons and two are nonbonding electrons.

illustration of electrons in acetonitrile

The bonding and nonbonding electrons are represented as shown:

Bonding and nonbonding electrons in acetonitrile