Phosphorus

Element 15 · Nonmetal

Specimen

Atomic number
15
Atomic mass
30.9738
State at room temperature
Solid
Melting point
44.15 °C
Boiling point
280.5 °C
Density
1.82 g/cm³
Discovered
1669

Physical data from PubChem.1

Can I eat it?

In food and water
Your body needs it. Phosphorus is a nutrient. The body uses it for energy, for cell structure, and to build bones and teeth. 2

See every element.

The atom

P
ShellElectrons
1 (K) 2
2 (L) 8
3 (M) outermost 5
Total15

Configuration [Ne] 3s² 3p³

3s ↑ ↓
3p ↑ ↑ ↑
A shell diagram: each ring is an electron shell and each dot is one electron. The nucleus holds 15 protons. The outermost shell is shown in red. Electrons do not travel on rings: they fill orbitals, regions where an electron is likely to be found. The boxes are those orbitals for the electrons outside the Ne core, with one arrow per electron.

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Sources

  1. 1

    National Center for Biotechnology Information (PubChem), 2026. Periodic Table of Elements .

    Atomic mass, electron configuration, melting and boiling points, density and discovery year for all 118 elements.

  2. 2

    European Food Safety Authority (EFSA), 2017. Dietary Reference Values for nutrients. Summary report (amended 2019) .

    Summaries of the EFSA NDA Panel opinions on each vitamin and mineral, section 4 (minerals) and section 5 (cobalamin).

    • Phosphorus is involved in many physiological processes, such as in the cell’s energy cycle ... as a component of the cell structure, in cell regulation and signalling, and in the mineralisation of bones and teeth