Final answer:
Salt in ocean water is not considered a mineral because it exists as dissolved sodium and chloride ions rather than a solid structure. Minerals are solid with definite chemical composition and crystalline structure, unlike dispersed ions in solution. Salt only forms a mineral structure when the water is evaporated and the ions crystallize.
Step-by-step explanation:
Although salt is present in ocean water, it is not considered a mineral when dissolved because it does not exist in a solid, structural form. In seawater, sodium ions and chloride ions are dispersed individually and only form the solid structure of sodium chloride, commonly known as table salt, once the water is completely evaporated.
Ordinary table salt, or sodium chloride, is a substance because it has a definite and uniform composition, which is not the case for saltwater where the concentration of dissolved salts can vary. Furthermore, minerals are typically defined as naturally occurring solids, having a definite chemical composition and crystalline structure. Salt in the ocean does not meet these criteria as it is in a dissolved ionic state, not solid.
The high salt content in the oceans is a result of dissolution, where sodium and chlorine atoms dissociate from their crystalline structure and become hydrated by water molecules. This process forms a solution in which the individual ions are dispersed throughout the water, as opposed to a solid mineral with a regular lattice structure, observable when salt is in its natural solid state, such as in halite deposits.