Question

Draw three resonance structures for CNO-. This species has its three atoms bonded sequentially in the following fashion: C-N-O. Draw your resonance structures so that the atoms in them are bonded together in this order. Select the most important resonance structure for this species based on the formal charges on the atoms of the three resonance structures you have drawn. Now select the statement from the multiple choices which is true about this most important resonance structure. In the most important resonance structure of CNO- : a) The leftmost bond (between C and N) is a double bond. b) The rightmost bond (between N and O) is a double bond. c) The formal charge on the leftmost (C) atom is -2. d) The number of nonbonding pairs (lone pairs) of electrons on the leftmost (C) atom is 2. e) The number of nonbonding (lone) pairs of electrons on the rightmost (O) atom is 3.

Answer 1

To calculate the charge of each atom.

Formal charge= Valence electrons-(non bonding electron+bonding electron/2)

The possible resonance of CNO- ( check attachment)

The second structure is the most stable because in this structure each atoms carry less formal charge than other.

(a) In the most stable resonance structure of CNO- leftmost bond is a triple bond.

Therefore the statement is False

(b) in the most stable resonance structure of CNO- rightmost bond is single.

Therefore the statement is true

(c) in the most stable resonance

structure of CNO- the formal charge on the leftmost is -1.

Therefore the statement is False

(d) in the most stable resonance structure of CNO-,the number of non bonding electron pairs on the leftmost carbon is 1.

Therefore the statement is False

(e) in the most stable resonance structure of CNO-the number of non bonding electron pairs on rightmost oxygen atom is 3.

Therefore the statement is False