Natrium and Na

Na and natrium are semantically related. In some cases you can use "Na" instead a noun "Natrium".

Na noun - A silvery soft waxy metallic element of the alkali metal group; occurs abundantly in natural compounds (especially in salt water); burns with a yellow flame and reacts violently in water; occurs in sea water and in the mineral halite (rock salt).

Natrium and na are semantically related. You can use "Natrium" instead a noun "Na".