What two substances are found in the greatest abundance among the major salts dissolved in sea water?

The salt water consists mostly of the following substances: dissolved salts (predominantly sodium (Na+) and chloride (Cl-) ions. The other most abundant ions of seawater are sulfate (SO24-), magnesium (Mg 2+), calcium (Ca 2+), and potassium (K+).

Average density at the surface is 1.025 kg/L. The two substance that can be seen in salt in sea water is sodium and chloride, seawater has approximately 35 grams (1.2 oz) of dissolved salts (predominantly sodium (Na+) and chloride (Cl-) ions). Seawater is denser than both fresh water and pure water (density 1.0 kg/L at 4 °C (39 °F)) because the dissolved salts increase the mass by a larger proportion than the volume.