How does sodium react with chlorine and other halogen gases?

Sodium, an alkali metal, reacts with halogen gases to form sodium salts, a process that reflects the naming of the halogens as "salt-producers". The reactivity of sodium with these gases decreases as the atomic weight of the halogen increases.12

When sodium reacts with chlorine, the process is highly exothermic, releasing a significant amount of heat. This reaction is analyzed through the Born-Haber cycle, which accounts for the energy required to vaporize the sodium, dissociate the chlorine molecules, and ionize the atoms, as well as the large amount of energy released during the formation of the crystalline ionic compound lattice. Under certain conditions, the reaction between sodium and halogen vapors can also produce light, a phenomenon known as chemiluminescence.31

Beyond direct reactions with elemental gases, sodium also reacts vigorously with halogen acids to yield sodium halides.1