Phosphorus (P): Electron Configuration, Properties and Uses
Phosphorus (P): Electron Configuration, Properties and Uses
Electron configuration [Ne] 3s2 3p3 · group 15 · period 3 · Ar 30.974
Phosphorus data
- Atomic number
- 15
- Relative atomic mass
- 30.974
- Group
- 15
- Period
- 3
- Block
- p
- Category
- Nonmetal
- Electron configuration
- [Ne] 3s2 3p3
- Full configuration
- 1s2 2s2 2p6 3s2 3p3
- Electrons per shell
- 2, 8, 5 (K L M)
- Valence electrons
- 5
- Electronegativity (Pauling)
- 2.19
- First ionisation energy
- 10.487 eV
- Atomic radius (van der Waals)
- 180 pm
- State at room temperature
- Solid
- Melting point
- 44.2 °C
- Boiling point
- 280 °C
- Density
- 1.82 g/cm³
- Common oxidation states
- +5, +3, −3
- Discovered
- 1669
Source: PubChem (NIH, accessed 13 Nov 2026); atomic mass: IUPAC standard atomic weight.
Electron shell diagram
K 2 · L 8 · M 5
Orbital diagram (outer electrons)
About phosphorus
Phosphorus is a chemical element with the symbol P and atomic number 15. It is a nonmetal in group 15, period 3, p-block. The element was discovered in 1669. Phosphorus is a solid that melts at 44.2 °C, just above body temperature.
Phosphorus electron configuration
The electron configuration of phosphorus is 1s2 2s2 2p6 3s2 3p3, or in short [Ne] 3s2 3p3. Its electrons occupy 3 shells: K = 2, L = 8, M = 5. Phosphorus has 5 valence electrons in the M shell (3s2 3p3), which is why it sits in group 15. In ionic compounds phosphorus gains electrons to fill its outer shell: P3− = [Ar] (like argon).
Filling order: 1s2(2) → 2s2(4) → 2p6(10) → 3s2(12) → 3p3(15)
Uses of phosphorus
The main uses of phosphorus include phosphate fertilisers, matches, phosphoric acid for drinks and metal treatment, and as part of DNA and ATP in cells. For research and analysis you can browse phosphate compounds in the AMI Scientific catalogue.
Safety
White phosphorus ignites spontaneously in air and is very toxic, so it is stored under water. Red phosphorus is much safer. Always read the safety data sheet (SDS) before working with a chemical.
Other elements in group 15
Frequently asked questions
What is the electron configuration of phosphorus?
The electron configuration of phosphorus (P, atomic number 15) is 1s2 2s2 2p6 3s2 3p3, or [Ne] 3s2 3p3 in short. By shell: 2, 8, 5.
How many valence electrons does phosphorus have?
Phosphorus has 5 valence electrons.
Which group and period is phosphorus in?
Phosphorus is in group 15, period 3, p-block.
What is the atomic mass of phosphorus?
The relative atomic mass of phosphorus is 30.974. Use it to calculate molar mass with the molar mass calculator.
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