1530.974PPhosphorus
Phosphorus (P) — element 15reactive nonmetal · group 15, period 3
Phosphorus is a chemical element with the symbol P and atomic number 15. It is a reactive nonmetal in group 15, period 3 of the periodic table (the p-block), with a standard atomic mass of 30.974 u. At room temperature (25 °C) phosphorus is a solid.
💡 Known for: Essential for DNA, ATP and bones; used in fertilisers and on the striking surface of matchboxes.
# Phosphorus properties
| Symbol | P |
|---|---|
| Atomic number | 15 |
| Atomic mass | 30.974 u |
| Category | reactive nonmetal |
| 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 |
| Protons / electrons | 15 / 15 |
| State at 25 °C | solid |
| Melting point | 317.3 K (44.2 °C, 111.5 °F) |
| Boiling point | 550 K (276.9 °C, 530.3 °F) |
| Density | 1.82 g/cm³ |
| Electronegativity (Pauling) | 2.19 |
| First ionization energy | 10.487 eV |
| Atomic radius | 98 pm |
| Discovered | 1669 |
# Electron configuration of phosphorus
The electron configuration of phosphorus is [Ne] 3s² 3p³, written out in full as 1s² 2s² 2p⁶ 3s² 3p³. Its 15 electrons fill 3 shells as 2, 8, 5, so the outermost shell holds 5 electrons. As a group 15 element, phosphorus has 5 valence electrons.
# Related elements
SiSiliconprevious elementSSulfurnext elementNNitrogengroup 15AsArsenicgroup 15SbAntimonygroup 15BiBismuthgroup 15McMoscoviumgroup 15HHydrogenreactive nonmetalCCarbonreactive nonmetalOOxygenreactive nonmetalSeSeleniumreactive nonmetal
# Phosphorus FAQ
What is the atomic number of phosphorus?
The atomic number of phosphorus is 15: every phosphorus atom has 15 protons in its nucleus. Its symbol is P.
What is the atomic mass of phosphorus?
The standard atomic mass of phosphorus is 30.974 u.
What is the electron configuration of phosphorus?
Phosphorus's electron configuration is [Ne] 3s² 3p³ (1s² 2s² 2p⁶ 3s² 3p³), with 2, 8, 5 electrons per shell.
Is phosphorus a metal?
No. Phosphorus is a reactive nonmetal, a nonmetal.
What is the melting point of phosphorus?
Phosphorus melts at 317.3 K (44.2 °C, 111.5 °F) and boils at 550 K (276.9 °C, 530.3 °F).
What is phosphorus used for / known for?
Essential for DNA, ATP and bones; used in fertilisers and on the striking surface of matchboxes.