Beryllium is a chemical element with the symbol Be and atomic number 4. It is a steel-gray, strong, lightweight, and brittle alkaline earth metal.

The commercial use of beryllium requires the use of appropriate dust control equipment and industrial controls at all times because of the toxicity of inhaled beryllium-containing dust that can cause a chronic, life-threatening allergic disease in some people called berylliosis.

Alkali Metals and Alkaline Earth Metals

The alkali metals (group 1) have very similar properties: they are all shiny, soft, highly reactive metals at standard temperature and pressure and readily lose their outermost electron to form cations with charge +1. The alkaline earth metals are all shiny, silvery-white, somewhat reactive metals at standard temperature and pressure.

The alkali metals are a group (column) in the periodic table consisting of the chemical elements lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr).