Beryllium (Be) — Atomic Number 4

Beryllium is a chemical element with the symbol Be and atomic number 4. It is a hard, grey-white alkaline earth metal. Unlike other Group 2 metals, it does not react with cold water. Its name comes from the mineral beryl, a gemstone known since antiquity.

At a Glance

Discovery

Discovered as an oxide by French chemist Louis-Nicolas Vauquelin in 1798. The metal was isolated in 1828 by Friedrich Wöhler and independently by Antoine Bussy.

Chemical Properties

Beryllium forms Be²⁺ ions (configuration 2, like helium). It is resistant to reaction with water due to a protective oxide layer.

Key Reactions

1. $2\text{Be}+{\text{O}}_2\to 2\text{BeO}$ (at high temperature)
2. $\text{Be}+2\text{HCl}\to {\text{BeCl}}_2+{\text{H}}_2$
3. $\text{Be}+2\text{NaOH}+2{\text{H}}_2\text{O}\to {\text{Na}}_2{\text{Be(OH)}}_4+{\text{H}}_2$ (amphoteric — reacts with alkali)

Uses

• Aerospace alloys — lightweight, stiff
• X-ray tube windows — transparent to X-rays
• Nuclear reactors — neutron reflector

Safety: Beryllium dust is highly toxic — causes incurable lung disease (berylliosis).

IGCSE Tips

• Group 2, Period 2 — has 2 outer electrons
• Amphoteric — reacts with both acids AND alkalis (unusual for a metal)
• Does NOT react with cold water (unlike Ca)

Sources

• Beryllium — Wikipedia
• Beryllium — Ptable.com
• Beryllium — RSC Periodic Table