Potassium is the third element in Group 1 of the periodic table. The elements in this group are commonly referred to as the alkali metals. Potassium has an atomic number of 19, an atomic mass of 39.0983, and a chemical symbol of K.

Properties

Potassium is a soft, silvery-white metal with a melting point of 145°F (63°C), a boiling point of 1,420°F (770°C), and a density of 0.862 grams per cubic centimeter. Its density is low enough that it will float if placed into water. Its melting point is low enough that the heat of a candle is sufficient to melt the metal.

Potassium is a very active metal that reacts violently with water to produce hydrogen gas: 2K + 2H₂O 2KOH + H₂ So much heat is produced in this reaction that the hydrogen gas tends to ignite and burn. Potassium also reacts readily with all acids and...