Boron (B)

From Wikipedia, the free encyclopediaBoron is a metalloid chemical element with symbol B and atomic number 5. Produced entirely by cosmic ray spallation and supernovae and not by stellar nucleosynthesis, it is a low-abundance element in both the Solar system and the Earth's crust. Boron is concentrated on Earth by the water-solubility of its more common naturally occurring compounds, the borate minerals.

Boron in the periodic table

SymbolB
Atomic number5
Group13
Period2
Blockp
Element categoryMetalloid

Physical properties

Phase at STPSolid
Density2.08 g/cm3
Atomic weight10.81 u
Melting point2349 K
2075.85 °C
3768.53 °F
Boiling point4200 K
3926.85 °C
7100.33 °F

Atomära egenskaper

Electronegativity (Pauling Scale)2.04
Electron affinity26.989 kJ/mol
Ionization energies
1800.6 kJ/mol
2 2427.1 kJ/mol
3 3659.7 kJ/mol
4 25025.8 kJ/mol
5 32826.7 kJ/mol

Electron configuration

Electron configuration1s2 2s2 2p1
Electrons per shell2, 3

History

Discovered1808
Discovered byJoseph Louis Gay-Lussac
Louis Jacques Thénard