Elemental sodium is a metal that on contact with water will create explosive hydrogen and due to the heat of the reaction will likely spontaneously catch fire in the process. The remainder of this reaction is Sodium Hydroxide which is the stuff used to make soap and burn hands in Fight Club.
Elemental chlorine is a toxic and corrosive gas that will cause severe chemical burns if you come into contact with it, will be fatal if inhaled at 0.1% concentration, and due to its oxidising nature will also cause a lot of common materials (wood, cotton, metal shavings, test engineers) to spontaneously combust.
Sodium chloride, being ordinary table salt, tastes good on steak and potatoes.