Question

How many lone pairs are there in $\text{C}{\text{O}}_{\text{2}}$?

Answer 1

Hint: Lone pair electrons are the electrons that don't form any bonds with other atoms and hence not involved in sharing. Lone pairs are found in the outermost electron shell of an atom. They can be identified by drawing Lewis dot structures. Lone pairs do not form any covalent bond. For example water contains two lone pairs of electrons.
Talking about Lewis dot structure it defines the nature of bond and position of atoms of molecules which are connected in molecules.

Complete step by step answer:
First of all we should find out the Lewis structure of $\text{C}{\text{O}}_{\text{2}}$
${}_{\bullet }^{\bullet }\stackrel{\bullet \bullet }{\text{O}}==\text{C}==\stackrel{\bullet \bullet }{\text{O}}{}_{\bullet }^{\bullet }$
In writing lewis dot structure first find the total number of electrons of valence shell, total electron pairs and then centre atom selection. Put lone pairs on atoms.
These are also called electron dot structure. These structure are mainly used to show lone pairs of the compound in $\text{C}{\text{O}}_{\text{2}}$
The central atom of this molecule is carbon.
Oxygen contains $6$ valence electrons and has a electronic configuration of $1s^{2}2s^{2}2p^4$ . It means there are two $p$ electrons that can form the double bound with carbon. This leans the $2$ pair of lone pairs that are not being used for bonding
Hence $2$ lone pairs are present at each Oxygen and the molecule contains two oxygen.
Carbon contains $4$ valence electrons which are making double bonds with each Oxygen. So Carbon contains no lone pairs on it.
So here we can conclude that the oxygen contains $2$ lone pairs so total four lone pairs are present in $\text{C}{\text{O}}_{\text{2}}$ molecule.

Note:
Only the valence electrons are considered while drawing Lewis dot structures and the electrons that do not belong to the outermost shell are ignored. Lewis structures are a useful way to summarize certain information about bonding and may be thought of as “electron bookkeeping” In drawing Lewis dot structures there should be a thorough knowledge of valence electrons of individual atoms so then only you can find out the lone pairs.