5 B 10.81

Boron

metalloid

Properties

Atomic number
5
Atomic mass
10.81 u
Category
metalloid
Group
13
Period
2
Block
p-block
State (room temp)
Solid
Outer-shell electrons
3
Electronegativity
2.04 (Pauling)
Density
2.08 g/cm³
Melting point
2075.85 °C
Boiling point
3926.85 °C

Electron configuration

1s² 2s² 2p¹

Noble-gas shorthand: [He] 2s² 2p¹

Electrons per shell: 2, 3 — that's 3 in the outermost shell.

See how electron configuration is built →

B
Bohr model — outer-shell electrons in blue

About Boron

Boron 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.

Position in the periodic table

Open the interactive periodic table →

Data compiled from Wikipedia, PubChem, and IUPAC. Source.