Question

Draw the Lewis structures for \({\rm{C}}{{\rm{O}}_{\rm{2}}}\)and\({\rm{CO}}\), and predict the number of \({\rm{\sigma }}\) and \({\rm{\pi }}\) bonds for each molecule.

(a) \({\rm{C}}{{\rm{O}}_{\rm{2}}}\)

(b) \({\rm{CO}}\)

Short answer

(a) There are two sigma and two pi bonds.

(b) There are two pi and one sigma bond.

Step-by-step solution

Definition of Concept

Lewis dot structure refers to the representation of bonding in ions or molecules and ions in terms of a shared pair of electrons in such a way that each atom, except hydrogen and helium, follows the octet rule.

Draw the Lewis structures

Because each carbon has four valence electrons and each oxygen has six, they will share two pairs of valence electrons and become stable. There is one sigma bond and one pi bond in a double bond, and since there are two double bonds, there will be two sigma and two double bonds. As a result, the Lewis structure for \({\rm{C}}{{\rm{O}}_{\rm{2}}}\) is:

Therefore, the required two sigma bonds and two pi bonds exist.

Draw the Lewis structures

Because each carbon has four valence electrons and each oxygen has six, they will share three pairs of valence electrons and become stable. Because a triple bond contains one sigma bond and two pi bonds, the Lewis structure for CO is:

Therefore, the required two pi bonds and one sigma bond exist.