D7 Rules for Drawing Lewis Structures for Molecules/Polyatomic Ions

Exceptions to the octet rule

Beryllium

When Be is the central atom in a molecule, it can be satisfied with 4 electrons.

Family 3A

When an atom from the Boron family is the central atom in a molecule, it can be satisfied with 6 electrons.

Family 4A

When an atom from the Carbon family (not including Carbon) is the central atom in a molecule, it can be satisfied with 6 electrons.

Family 5A

When an atom from the Nitrogen family (not including Nitrogen) is the central atom in a molecule, it can be satisfied with 10 electrons.

Family 6A

When an atom from the Oxygen family (not including Oxygen) is the central atom in a molecule, it can be satisfied with 12 electrons.

Halogen and Noble Gas Atoms

Can have extra lone pairs of electrons when they are the central atom