4
Be
Beryllium
9.01218315
Beryllium (Be)
Alkaline Earth MetalGroup 2Period 2s-block-block
Beryllium is a chemical element with symbol Be and atomic number 4. It is created through stellar nucleosynthesis and is a relatively rare element in the universe. It is a divalent element which occurs naturally only in combination with other elements in minerals.
Latin name: Beryllium
Atomic Number
4
Atomic Mass
9.01218315 g/mol
Phase (STP)
Solid
Electron Config.
[He] 2s²
General
SymbolBe
Atomic Number4
Atomic Mass9.01218315 g/mol
CategoryAlkaline Earth Metal
Group2
Period2
Blocks-block
Electron Configuration[He] 2s²
Valence Electrons2
ColourWhite-gray metallic
Appearancewhite-gray metallic
CAS NumberCAS7440-41-7
Physical Properties
Phase (STP)Solid
Density1.85 g/cm³
Melting Point1286.85°C · 2348.33°F · 1560.00 K
Boiling Point2468.85°C · 4475.93°F · 2742.00 K
Atomic Properties
Atomic Radius112 pm
Covalent Radius96 pm
Electronegativity1.57 Pauling
Ionization Energy899 kJ/mol
Oxidation States+2
Ion ChargeBe²⁺
Thermodynamic
Molar Heat16.443 J/(mol·K)
Thermal Conductivity200 W/(m·K)
Electromagnetic
Electrical TypeConductor
Crystal Structure
Crystal StructureHexagonal close-packed
Mechanical Properties
Mohs Hardness5.5
Abundance
In Universe0.00001%
In Sun0.000000001%
In Earth's Crust0.0280%
In Oceans0.00000000006%
In Humans0.000000004%
In Meteorites0.0003%
Discovery & History
Discovery Year1798
Discovered ByLouis Nicolas Vauquelin
Isotopes of Beryllium
| Isotope | Abundance | Half-life | Decay |
|---|---|---|---|
| Be-7 | — | 53.22 days | EC, β⁺ |
| Be-9 | 100% | Stable | — |
| Be-10 | — | 1.39 × 10⁶ years | β⁻ |