IB CHEMISTRY

HL Only

2.2.14 Formal Charge

Selecting the preferred Lewis structure.

Calculation Formula

FC = (Valence e⁻) - (Non-bonding e⁻) - ½(Bonding e⁻)

Selection Rules

  • Preferred structure has formal charges closest to 0.
  • If charges exist, negative FC should be on the most electronegative atom.