Why is phosphorus in group 5 periodic table?

Group 5A (or VA) of the Periodic Table are the pnictogens: the nonmetals nitrogen (N), and phosphorus (P), the metalloids arsenic (As) and antimony (Sb), and the metal bismuth (Bi). The name "pnictogen" is not in common usage; it derived from the Greek work pnigein, "choke" or "stifle," which is a property of breathing pure nitrogen gas.

The Group 5A elements have five valence electrons in their highest-energy orbitals (ns2np3). Nitrogen, phosphorus, and arsenic can form ionic compounds by gaining three electrons, forming the nitride (N3-), phosphide (P3-) and arsenide (As3-) anions, but they more frequently form compounds through covalent bonding. Antimony and bismuth can lose either their outermost p electrons to form 3+ charges, or their outermost s and p electrons to form 5+ charges.

Compounds of Group 5 Elements

The title of this lesson doesn't really do the topic justice. Compounds made from elements in Group 5 of the periodic table can help athletes increase endurance and build muscle. They're involved in making chemical weapons used in war. And, you might even them find in your favorite beverages.