Boron (B): Electron Configuration, Properties and Uses
Boron (B): Electron Configuration, Properties and Uses
Electron configuration [He] 2s2 2p1 · group 13 · period 2 · Ar 10.81
Boron data
- Atomic number
- 5
- Relative atomic mass
- 10.81
- Group
- 13
- Period
- 2
- Block
- p
- Category
- Metalloid
- Electron configuration
- [He] 2s2 2p1
- Full configuration
- 1s2 2s2 2p1
- Electrons per shell
- 2, 3 (K L)
- Valence electrons
- 3
- Electronegativity (Pauling)
- 2.04
- First ionisation energy
- 8.298 eV
- Atomic radius (van der Waals)
- 192 pm
- State at room temperature
- Solid
- Melting point
- 2075 °C
- Boiling point
- 4000 °C
- Density
- 2.37 g/cm³
- Common oxidation states
- +3
- Discovered
- 1808
Source: PubChem (NIH, accessed 13 Nov 2026); atomic mass: IUPAC standard atomic weight.
Electron shell diagram
K 2 · L 3
Orbital diagram (outer electrons)
About boron
Boron, symbol B, is element number 5 in the periodic table. It is a metalloid in group 13, period 2, p-block. The element was discovered in 1808. Boron is a solid at room temperature, melting at 2075 °C and boiling at 4000 °C.
Boron electron configuration
The electron configuration of boron is 1s2 2s2 2p1, or in short [He] 2s2 2p1. Its electrons occupy 2 shells: K = 2, L = 3. Boron has 3 valence electrons in the L shell (2s2 2p1), which is why it sits in group 13.
Filling order: 1s2(2) → 2s2(4) → 2p1(5)
Uses of boron
Well-known applications of boron include borosilicate laboratory glassware, boric acid, neodymium (NdFeB) magnets and nuclear reactor control rods. For research and analysis you can browse boron compounds in the AMI Scientific catalogue.
Safety
Elemental boron has low toxicity. Boric acid and borax must not be used as food additives. Always read the safety data sheet (SDS) before working with a chemical.
Other elements in group 13
Frequently asked questions
What is the electron configuration of boron?
The electron configuration of boron (B, atomic number 5) is 1s2 2s2 2p1, or [He] 2s2 2p1 in short. By shell: 2, 3.
How many valence electrons does boron have?
Boron has 3 valence electrons.
Which group and period is boron in?
Boron is in group 13, period 2, p-block.
What is the atomic mass of boron?
The relative atomic mass of boron is 10.81. Use it to calculate molar mass with the molar mass calculator.
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