Covalent bonds in CO2 Lewis structure

Steps:

• CO2 formula is O=C=O, with carbon central and bonded to two oxygens.
• Carbon forms a double bond with each oxygen atom.
• Each double bond shares 4 electrons, equivalent to 2 pairs.
• Two double bonds yield 4 shared pairs total.

Why B is correct:

• Lewis structure of CO2 shows two C=O double bonds; each double bond is 2 shared pairs by definition of covalent bonding.

Why the others are wrong:

• A: Counts only the bonds as single pairs, ignoring double bond nature.
• C: Counts total valence electrons (16) instead of shared pairs.
• D: Counts all valence electrons (24) or misapplies octet rule.

Final answer: B