Beryllium

Symbol: Be
Atomic number: 4
Category: alkaline earth metals
Group: 2
Period: 2
Block: s
Atomic weight: 9.012182 g/mol
Electrons per shell: 2, 2
CAS number: 7440-41-7
Phase: solid
Density: 1.85 kg/dm³ (near room temperature)
Melting point: 1560 K (1278 °C, 2349 °F)
Boiling point: 2742 K (2469 °C, 4476 °F)
Crystal structure: hexagonal
Oxidation states: 3, 2, 1
Electronegativity: 1.57 (Pauling scale)
Name's origin: beryllos
Name's meaning: to become pale, in reference to the pale semiprecious gemstone beryl
Facts:
- has one of the highest melting points of the light metals
- is used as an alloying agent in the production of beryllium copper, which contains up to 2.5 % beryllium
- all beryllium compounds are carcinogenic to both animals and humans