P
Phosphorus
Element 15 · Reactive nonmetal
Phosphorus (P)
Phosphorus is a reactive nonmetal found in DNA, bones and the energy molecule ATP. Its white form glows and ignites spontaneously in air.
- Reactive nonmetal
- Period 3
- Group 15
- p-block
- solid at room temperature
Key properties
- Atomic mass
- 30.9738
- u
- Electron configuration
- [Ne] 3s2 3p3
- Melting point
- 44.2 °C
- 317.3 K
- Boiling point
- 280.5 °C
- 553.65 K
- Density
- 1.82 g/cm³
- Electronegativity
- 2.19
- Pauling
- Atomic radius
- 180 pm
- van der Waals
- 1st ionisation energy
- 10.487 eV
Compare with every element:Electronegativity chartAtomic radius chartIonisation energy chartDensity chart of the elementsMelting point chartElectron configuration chart
Did you know?
Notable facts about phosphorus
- 01
Brand discovered it by boiling down about 1,500 gallons of urine while searching for the philosopher’s stone.
- 02
It was the first element whose discoverer is known.
- 03
Red phosphorus on the side of a matchbox is what makes safety matches strike.
Applications
What is phosphorus used for?
- Fertilisers (phosphates)
- Safety matches
- Detergents and water treatment
- Steel and bronze alloys
History
Discovery & name origin
Discovered by
Year
Where
Germany
Name origin
Greek phosphoros, “light-bearer” — white phosphorus glows in the dark.
Atomic structure
Atomic properties
Atomic structure
Atomic properties
- Atomic number
- 15
- Atomic mass
- 30.9738 u
- Group
- 15
- Period
- 3
- Block
- p-block
- Electron configuration
- [Ne] 3s2 3p3
- Full configuration
- 1s2 2s2 2p6 3s2 3p3
- Electrons per shell
- 2, 8, 5
- Electronegativity (Pauling)
- 2.19
- Electron affinity
- 0.746 eV
- Atomic radius (van der Waals)
- 180 pm
- Stable isotopes
- 1
Oxidation states
Highlighted: common oxidation states (+5, +3, -3).
Successive ionisation energies
Energy to remove each electron in turn (kJ/mol). Big jumps show where a new, inner shell begins.
- 1st1,011.8
- 2nd1,907
- 3rd2,914.1
- 4th4,963.6
- 5th6,273.9
- 6th21,267
- 7th25,431
- 8th29,872
Physical
Physical properties & colour
Physical
Physical properties & colour
- State at 20 °C
- Solid
- Melting point
- 317.3 K · 44.2 °C · 111.5 °F
- Boiling point
- 553.65 K · 280.5 °C · 536.9 °F
- Density
- 1.82 g/cm³
- Molar heat capacity
- 23.824 J/(mol·K)
- Appearance
- Colourless, waxy white, yellow, scarlet, red, violet, black
- CPK model colour
- Copied
The CPK colour is the convention used for this element’s atoms in molecular models.
FAQ
Phosphorus questions
What is P on the periodic table?
P is the symbol for phosphorus, element 15 on the periodic table. It sits in group 15, period 3, in the reactive nonmetal category, and has an atomic mass of 30.9738.
What is the atomic number of phosphorus?
Phosphorus has atomic number 15, so every phosphorus atom has 15 protons in its nucleus. Its symbol is P and its atomic mass is 30.9738.
Who discovered phosphorus?
Phosphorus was discovered by Hennig Brand in 1669 (Germany). The name comes from Greek phosphoros, “light-bearer” — white phosphorus glows in the dark.
What is phosphorus used for?
Phosphorus is used for: fertilisers (phosphates); safety matches; detergents and water treatment; steel and bronze alloys.
Is phosphorus a metal?
No. Phosphorus is classed as a reactive nonmetal.
What is the electron configuration of phosphorus?
The electron configuration of phosphorus is [Ne] 3s2 3p3. Its 15 electrons are arranged in shells as 2, 8, 5.