Element 5
Boron (B)
Boron (B) is element 5 of the periodic table, a metalloid in period 2, group 13 (p-block) with an atomic mass of 10.81 and is a solid at standard conditions.
At a glance
- Atomic number
- 5
- Symbol
- B
- Atomic mass
- 10.81 u
- Category
- Metalloids
- Period
- 2
- Group
- 13
- Block
- p-block
- Phase at STP
- solid
Electron structure
- Electron configuration
- 1s2 2s2 2p1
- Shorthand configuration
- [He] 2s2 2p1
- Electrons per shell
- 2, 3
- Oxidation states
- +3
Physical properties
- Melting point
- 2349 K
- Boiling point
- 4200 K
- Density
- 2.34 g/cm3
- Phase
- solid
Atomic properties
- Electronegativity (Pauling)
- 2.04
- Atomic radius
- 87 pm
- Covalent radius
- 84 pm
- Van der Waals radius
- 192 pm
- First ionization energy
- 801 kJ/mol
- Electron affinity
- 27 kJ/mol
Notable isotopes
| Isotope | Mass | Abundance | Stability |
|---|---|---|---|
| B-11 | 11.00931 | 80.1% | Stable |
Common uses
- Fiberglass
- Ceramics
- Detergents
- Semiconductors
Discovery
- Year
- 1808
- Discovered by
- Joseph Louis Gay-Lussac, Louis Jacques Thénard
- Country
- France