1: Nitrogen atom, 2: Oxygen atoms, 3: Single bond, 4: Double bond, 5: Lone pairs, 6: Negative charge

1: Sulfur (S), 2: Carbon (C), 3: Nitrogen (N), 4: Single bond, 5: Triple bond, 6: Lone pairs

1: Phosphorus atom, 2: Oxygen atoms, 3: Single bonds, 4: Lone pairs, 5: +1 Formal Charge on P, 6: -1 Formal Charge on O

1: Phosphorus atom, 2: Oxygen atoms, 3: Single bonds, 4: Double bond, 5: Lone pairs, 6: Formal charge of 0 on P and one O, -1 on the other three O

1: Sulfur (S) atoms, 2: Chlorine (Cl) atoms, 3: Single bonds, 4: Lone pairs on S, 5: Lone pairs on Cl

Resonance Structures: Represent different ways of drawing the same molecule, differ only in electron arrangement. | Isomers: Are different molecules with the same molecular formula, but different arrangements of atoms.

Formal Charge: Assumes equal sharing of electrons in a bond. | Oxidation Number: Assumes the more electronegative atom gets all the shared electrons.

Resonance is when a single Lewis structure cannot fully represent the bonding in a molecule, and the true structure is a hybrid of multiple resonance structures.

Bond order is the number of chemical bonds between a pair of atoms. It can be a fraction in molecules exhibiting resonance.

Formal charge is the charge assigned to an atom in a molecule, assuming that electrons in all chemical bonds are shared equally between atoms.

A resonance hybrid is the actual electronic structure of a molecule or ion, which is represented by a combination of several resonance structures.

Formal Charge = (Valence Electrons) - (Lone Pair Electrons) - (Number of Bonds)