All practice pages/Interatomic theory/Elements
Element 4, an alkaline earth metal
A light, stiff metal that X-rays pass straight through, and one of the more dangerous elements to breathe in as dust.
Period 2, group 2. The other alkaline earth metals are tinted, and every cell opens its own article.
Two valence electrons, but beryllium is so small that its bonds are more covalent than those of the other alkaline earth metals. In its ionic compounds it is Be²⁺.
Rare in the crust. It comes mainly from bertrandite mined in Utah and from beryl, the mineral whose green and blue gem forms are emerald and aquamarine.
Louis-Nicolas Vauquelin found its oxide in beryl and emerald in 1798, and Friedrich Wöhler and Antoine Bussy each isolated the metal in 1828. It was long called glucinium, from the Greek for sweet, because its salts taste sweet. The name beryllium, from beryl, became official in 1949.
Windows for X-ray tubes and detectors, because X-rays pass through it. Copper-beryllium alloys make springs, electrical contacts and non-sparking tools for oil rigs and mines. It is light and stiff enough for aerospace parts: the 18 mirror segments of the James Webb Space Telescope are gold-coated beryllium.
Breathing beryllium dust or fumes can cause chronic beryllium disease, a lasting lung illness, so machining it needs strict dust control. Never taste its compounds.