Which of the following correctly identifies a characteristic of oxidation states?

The correct identification of a characteristic of oxidation states is that they must add up to the charge on the molecule. In any chemical species, whether it is a neutral molecule or an ion, the sum of the oxidation states of all the atoms must equal the overall charge of that species. For example, in a neutral molecule, the total oxidation states will sum to zero, while in a charged ion, the sum corresponds to the ion's charge. This is essential for determining how electrons are distributed among the atoms in the compound.

To add additional context, while oxidation states can be positive, negative, or zero, they must also accurately reflect the electron transfer occurring in a reaction. It’s also important to note that they are not restricted to integer values in all scenarios, as some representations may involve fractional oxidation states, especially in complex compounds. Hence, the only accurate characteristic highlighted is the relationship between the sum of oxidation states and the overall charge of the molecule.