
Salts: The main portion of salts in oceans is Sodium Chloride(Nacl) concentration of about 3 percent and hence elements more than 80 percent of the dissolved chemical compounds in sea water.
Potassium and Magnesium: The average concentration of Potassium is about 1300 parts per million and Magnesium is about 1000 parts per million.
Others: Limestone,Gypsum,Manganese,Phosphorites,Gold,Tin,Platinum are available as a chemical compounds which need to be extracted to get those precious objects.
If you have any comment then please do not forget to comment.Thanks.