The heats of atomization of elements are heats of dissociation of diatomic gas molecules such as H₂, N₂, O₂, or F₂, or of vaporization of solids such as graphite and sulfur into atoms. Since the standard state of sulfur is a solid made up of packed S₈ rings, atomization would entail first breaking van der Waals forces and evaporating the S₈ molecules, then taking them apart into isolated sulfur atoms.

Notice how the heats of atomization agree roughly with the number of bonds formed by each atom: four bonds in graphite, a triple N�N bond in N₂, a double bond in O=O, and a single bond in F-F. The single bond in H-H is almost as strong as the double bond in O=O because the H atoms are small and can get close to one another.

The C=C double bond is not quite twice as strong as a single bond because the second shared electron pair does not have as favorable geometry for bonding as does the first pair.

For the same reason, a triple bond is not three times as strong as a single bond. Carbon binds to hydrogen more strongly than to another carbon because of hydrogen's small size and the closer approach of atomic centers.