Question

(i) With suitable example, explain the
concept of formal charge.​

Answer 1

Explanation:

For example, carbon dioxide or CO2 is a neutral molecule that has 16 valence electrons. There are three different ways to draw the Lewis structure for the molecule to determine formal charge:

The carbon atom may be joined to both oxygen atom via double bonds (carbon = 0, oxygen = 0, formal charge = 0)

The carbon atom may have a single bond with one oxygen atom and a double bond to the other oxygen atom (carbon = +1, oxygen-double = 0, oxygen-single = -1, formal charge = 0)

The carbon atom may be joined to each oxygen atom via single bonds (carbon = +2, oxygens = -1 each, formal charge = 0)

Each possibility results in a formal charge of zero, but the first choice is the best one because it predicts no charge in the molecule. This is more stable and thus is most likely.

See how to calculate formal charge with another example problem