Metallic element and Sodium

Metallic element noun - Any of several chemical elements that are usually shiny solids that conduct heat or electricity and can be formed into sheets etc..

Sodium and metallic element are semantically related. In some cases you can replace term "Sodium" with "Metallic element", this terms are similar.

Sodium 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).

Metallic element and sodium are semantically related. You can use "Metallic element" instead a noun "Sodium".