5B10.810
Metalloidp-block
Boron
Element 5 on the periodic table, symbol B, group 13, period 2.
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.
Appearance: black-brown
Properties
- Atomic Number
- 5
- Atomic Mass
- 10.8100 u
- Group
- 13
- Period
- 2
- Block
- p-block
- Category
- Metalloid
- State at 25 °C
- Solid
- Melting Point
- 2,349 K · 2,075.9 °C
- Boiling Point
- 4,200 K · 3,926.9 °C
- Density
- 2.08 g/cm³
- Atomic Radius
- 85 pm
- Electronegativity
- 2.04
- Oxidation States
- +3
- Abundance in Crust
- 10 mg/kg
- Discovered
- 1808
- Discovered By
- Joseph Louis Gay-Lussac
Electron Configuration
[He] 2s2 2p1
1s2 2s2 2p1
Ionisation Energies (kJ/mol)
- 1. 800.6
- 2. 2,427.1
- 3. 3,659.7
- 4. 25,025.8
- 5. 32,826.7
Elements near Boron
Elements in the same group share the number of outer electrons and behave in similar ways. Elements in the same period share a shell, so they change steadily from left to right.