Question

Recall that a carbon atom behaves as if it possesses four valence electrons. given this information, what is the most likely structural formula for carbon dioxide (co2)?

Answer 1

Carbon (C) belongs to Group IV A in the periodic table.

Atomic number of C = 6

Electron configuration = $1s^{2}2s^{2}2p^{2}$

Oxygen (O) belongs to group VI A in the periodic table

Atomic number of O = 8

Electron configuration = $1s^{2} 2s^{2} 2p^{4}$

Based on the electron configurations, the valence shell in C and O have 4 and 6 electrons respectively. As a result carbon is tetravalent, and in CO2 this is satisfied as the C atom forms a double bond with each O atom. Hence the structural formula is:  

O=C=O

In addition, there are two lone pairs of electrons on each of the O atoms.