It could also be the fact that the element chlorine Cl 17 its only missing 1 electron to be stable like Argon 18 in where its valence shell is full and Sodium Na 3 have 1 extra electron to be stable like Helium 2. Therefore chlorine really wants an extra electron and sodium wants to lose it. This makes the ion NaCl which is present in earth
Its probably becuase of the amount of minerals found in the ocean floor.Salt just so happens to be a major one.not only that,but the amount of salt that the human body emits while while outside,normally by bodies of water,it could also be that.
