phosphorus (P), nonmetallic chemical element of the nitrogen family (Group 15 [Va] of the periodic table) that at room temperature is a colourless, semitransparent, soft, waxy solid that glows in the dark.

Phosphorus is the 15th element in the periodic table and has a symbol of P and atomic number of 15. It has an atomic weight of 30.97376 and a mass number of 31. Phosphorus has fifteen protons and sixteen neutrons in its nucleus, and fifteen electrons in three shells. It is located in group fifteen, period three and block p of the periodic table.

Phosphorus is a chemical element of the periodic table with chemical symbol P and atomic number 15 with an atomic weight of 30.9738 u and is classed as nonmetal and is part of group 15 (nitrogen group). Phosphorus is solid at room temperature.

With the periodic table symbol P, atomic number 15, atomic mass of X g.mol-1, and electron configuration X, phosphorus is a nonmetal substance with 3 main allotropes – black, red, and white.