Metals, Alkali, Very Active

The alkali metals are nonflammable, but they are combustible. They may also burn in carbon dioxide and in nitrogen. Their reaction with water is violently rapid and quite exothermic. It produces gaseous hydrogen and other products. The heat that is generated is sufficient to melt the unreacted metal, ignite the liberated hydrogen and ignite the metal itself.

Materials in this group react, usually vigorously, with any substance having active hydrogen atoms to liberate gaseous hydrogen. This includes alcohols and acids, and most importantly, water. They react with sulfides, oxidizing agents, aldehydes, and cyanides. They corrode rapidly on contact with the air, becoming coated with white oxides and peroxides. As a practical matter, most other organic compounds, including ethers, are wet enough (carry enough water as an impurity) to cause heating and liberation of gases in contact with alkali metals. Alkali metals and alloys containing alkali metals are all powerful reducing agents.

All the materials in this group react with moisture to generate caustic products (hydroxides). Contact with these metals with the skin can cause chemical burns by the action of these products and thermal burns from the heat of the reaction.

Materials in this group are the elements in the Group IA of the periodic table and their alloys.

Cesium, lithium, potassium, sodium, rubidium, sodium amalgam, NaK (sodium-potassium alloy).