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Periodic table · chemistry · physics
Element story

Phosphorus

Atomic number 15 means that every Phosphorus nucleus contains 15 protons. That proton count is the element's identity: change it and you no longer have Phosphorus.

Start with the nucleus

Atomic number 15 means that every Phosphorus nucleus contains 15 protons. That proton count is the element's identity: change it and you no longer have Phosphorus.

Phosphorus (P) is chemical element 15. It belongs to the nonmetals, and its reference state at room temperature is a solid. Those basic facts are a useful starting point for its chemistry and applications.

In practice, it turns up most often in fertiliser production, biology and matches.

See the atom

Conceptual visual: electron shells are a learning aid, not a literal picture of quantum orbitals.

What this number means

Atomic number 15 means that every Phosphorus nucleus contains 15 protons. That proton count is the element's identity: change it and you no longer have Phosphorus.

Keep exploring

→ Phosphorus · Atomic structure · Periodic trends

15PPhosphorus
Phosphorus · P · Z = 15

Phosphorus (P) is chemical element 15. It belongs to the nonmetals, and its reference state at room temperature is a solid. Those basic facts are a useful starting point for its chemistry and applications.

Understanding the element

Phosphorus (P) is chemical element 15. It belongs to the nonmetals, and its reference state at room temperature is a solid. Those basic facts are a useful starting point for its chemistry and applications.

Where do we encounter it?

In practice, it turns up most often in fertiliser production, biology and matches.

What its position in the table tells us

Phosphorus sits in period 3, group 15 and the P block. That location is useful because neighbouring elements often share trends in valence electrons, oxidation states and bonding behaviour.