When sodium and chlorine atoms come together to form sodium chloride (NaCl), they transfer an electron. Because the sodium ion has a positive charge, and the chlorine ion has a negative charge, they are attracted to each other, and form an ionic bond.

Sodium has one valence electron, and chlorine has seven. The one sodium electron can be donated to chlorine, and chlorine holds onto the two electrons that are in the Na−Cl ionic bond.

The number of valence electrons determines how these reactions take place and what kind of bonds atoms can form. The Ione valence electron from sodium is lost and is transferred to the chlorine atom. The result is a sodium ion with a charge of 1+ and a chloride ion with a charge of 1-.

When a sodium atom transfers an electron to a chlorine atom, forming a sodium cation (Na+) and a chloride anion (Cl-), both ions have complete valence shells, and are energetically more stable. The reaction is extremely exothermic, producing a bright yellow light and a great deal of heat energy.

Why Dissolving Salt Is a Chemical Change Therefore, dissolving salt in water is a chemical change. The reactant (sodium chloride, or NaCl) is different from the products (sodium cation and chlorine anion). Thus, any ionic compound that is soluble in water would experience a chemical change.

When sodium chloride is dissolved in water, the polar water molecules are able to work their way in between the individual ions in the lattice. The water molecules surround the negative chloride ions and positive sodium ions and pull them away into the solution. This process is called dissociation.

If you dissociate, you may feel disconnected from yourself and the world around you. For example, you may feel detached from your body or feel as though the world around you is unreal. Remember, everyone’s experience of dissociation is different.

This is a normal process that everyone has experienced. Examples of mild, common dissociation include daydreaming, highway hypnosis or “getting lost” in a book or movie, all of which involve “losing touch” with awareness of one’s immediate surroundings.

In chemistry, dissociation is the breakdown of a substance into smaller particles such as atoms, ions or molecules. When an ionic compound is dissolved in water, it is dissociated into its ionic constituents. When NaCl is dissolved in water, the resulting solution contains Na+ cations and Cl– anions.

Glucose (sugar) readily dissolves in water, but because it does not dissociate into ions in solution, it is considered a nonelectrolyte; solutions containing glucose do not, therefore, conduct electricity.