Atomic number 5
Boron
Metalloid
Quick facts
- Atomic mass
- 10.810
- Group
- 13
- Period
- 2
- State (STP)
- solid
- Electronegativity
- 2.04
- Common ox. states
- +3
Properties
Electron configuration
[He] 2s² 2p¹
- Ionization energy
- 800.6 kJ/mol
- Electron affinity
- 26.7 kJ/mol
- Melting point
- 2349.00 K (2075.8 °C)
- Boiling point
- 4200.00 K (3926.8 °C)
How it bonds
Boron has three valence electrons and forms three covalent bonds — but unlike carbon, it stops there. BF₃ is famous for having only 6 electrons around boron (an "incomplete octet"), which makes it a Lewis acid: it eagerly grabs a lone pair from another molecule (like NH₃) to complete its octet.
Where you meet it
- Build Boron trifluorideBF₃
- Periodic Quest challengeunlock card