Find the total number of valence electrons on the central atom
Count the number of electrons used in bonding around the central atom
Subtract the bonding electrons from the valence electrons
Divide the remaining electrons by 2
The result is the number of lone pairs on the central atom
Use the formula: Lone pairs = (Valence electrons – Bonding electrons) / 2
For a neutral atom, valence electrons come from its group number
For ions, add electrons for negative charge and subtract electrons for positive charge before calculating
Each single bond uses 2 electrons
Each double bond uses 4 electrons
Each triple bond uses 6 electrons