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Phosphorus

Element 15 · Nonmetal

Specimen

Atomic number
15
Atomic mass
30.974
State at room temperature
Solid
Melting point
44.15 °C
Boiling point
280.5 °C
Density
1.82 g/cm³
Discovered
1669

Atomic mass from IUPAC.1 Other physical data from PubChem.2

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. 3

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.

Related elements

Group 15
N Nitrogen As Arsenic Sb Antimony Bi Bismuth Mc Moscovium

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Sources

  1. 1

    IUPAC Commission on Isotopic Abundances and Atomic Weights (CIAAW), 2024. Abridged Standard Atomic Weights 2024 .

    The atomic mass shown for the 84 elements that have a standard atomic weight.

  2. 2

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

    Electron configuration, melting and boiling points, density and discovery year for all 118 elements.

  3. 3

    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
  4. 4

    National Institute of Standards and Technology (NIST), 2026. Atomic Weights and Isotopic Compositions for All Elements .

    Isotopic composition of each element; the most abundant isotope sets the neutron count in the nucleus view.