Group 15 elements have five valence electrons (ns2 np3). Common oxidation states are -3, +3 and +5. The range of oxidation state is from -3 to +5.
Group 15 elements exhibit positive oxidation states such as +3 and +5. Due to inert pair effect, the stability of +5 oxidation state decreases and +3 oxidation state increases on moving down the group.
Group 15 elements show tendency to donate electron pairs in -3 oxidation state. This tendency is maximum for nitrogen.
The group 15 elements achieve +5 oxidation state only through covalent bonding.
e. g. NH3, PH3, ASH3, SbH3, and BiH3 contain 3 covalent bonds. PCl5 and PF5 contain 5 covalent bonds.
