Topic overview

Start with the big picture

The group’s trends reflect both its shared electron configuration and the increasing size and metallic character of its elements down the group. Atomic and ionic radii increase, while ionization energy and electronegativity generally decrease; half-filled stability helps explain why ionization energies remain relatively high compared with neighboring groups. Oxidation-state stability shifts from −3 and +5 toward +3 down the group, consistent with the inert-pair effect. Bonding and compound properties change as well: nitrogen is distinctive in multiple bonding and complex formation, while hydride stability and basicity decrease down the group. Oxides shift from acidic toward basic character, and halide stability varies with oxidation state. Together, these relationships provide a framework for comparing the elements and their compounds.