15 P 30.974

Phosphorus

polyatomic nonmetal

Properties

Atomic number
15
Atomic mass
30.974 u
Category
polyatomic nonmetal
Group
15
Period
3
Block
p-block
State (room temp)
Solid
Outer-shell electrons
5
Electronegativity
2.19 (Pauling)
Density
1.823 g/cm³
Melting point
Boiling point

Electron configuration

1s² 2s² 2p⁶ 3s² 3p³

Noble-gas shorthand: [Ne] 3s² 3p³

Electrons per shell: 2, 8, 5 — that's 5 in the outermost shell.

See how electron configuration is built →

P
Bohr model — outer-shell electrons in blue

About Phosphorus

Phosphorus is a chemical element with symbol P and atomic number 15. As an element, phosphorus exists in two major forms—white phosphorus and red phosphorus—but due to its high reactivity, phosphorus is never found as a free element on Earth. Instead phosphorus-containing minerals are almost always present in their maximally oxidised state, as inorganic phosphate rocks.

Position in the periodic table

Open the interactive periodic table →

Data compiled from Wikipedia, PubChem, and IUPAC. Source.