3) In hardware design, a prototype is a hand-built model that represents a manufactured (easily replicable) product sufficiently for designers to visualize and test the design. The word prototype comes from the Latin words proto, meaning original, and typus, meaning form or model.
In chemistry, a salt is an ionic compound which is made up of two groups of oppositely charged ions. The ion with a positive charge is called a cation, and the one with a negative charge is called an anion.
sodium. n. 1. (Elements & Compounds). a. a very reactive soft silvery-white element of the alkali metal group occurring principally in common salt, Chile saltpetre, and cryolite. Sodium and potassium ions maintain the essential electrolytic balance in living cells.