namely Hydrogen, Oxygen, Sodium, Chlorine and some others
sodium and chlorine
yes
the main element extracted was radium
No, it is a mixture of a number of different compound. Water itself is a compound. Ocean water is not pure water though.
sodium chloride
Ocean water is a mixture.
Calcium.
Einsteinium is not extracted from the earth, it is an artificial element.
Sodium chloride (salt) is the most commonly extracted element from seawater. Other elements that can be extracted include magnesium, calcium, and potassium.
The element Sodium (Na) was first extracted in 1807. It is very soft and burns on contact with water.
No, it is the most common dissolved ion in the ocean. The most common element by mass is oxygen as the ocean is still mostly water.
Lithium is extracted as the molten metal by a process of electrolysis.