Nitrogen, phosphorus, arsenic, antimony and bismuth are all members of group 15 of the periodic table. Nitrogen is a gas, phosphorus a non-metal, arsenic and antimony are metalloids, and bismuth is a metal. The group trend is towards an increasingly metallic character.
None of the members of the group are good conductors of electricity. Arsenic and antimony possess semiconductor properties, their electrical resistivity lying midway between that of a metal and that of an insulator, and are used in electronic components. Bismuth is less efficient as a conductor than are arsenic and antimony.
Both nitrogen and phosphorus are essential presences in living organisms. Nitrogen is an important constituent of proteins; phosphorus is crucial to metabolic reactions, and is also to be found in chromosomes.
Arsenic, antimony and bismuth have relatively low melting and boiling points. Bismuth, in particular, when compared to other metals, is extremely easy to melt.
All the members of the group have an unpaired electron in each of the three p shells. But the clear trends of certain other groups - rising melting points, and so on - are not generally apparent in this group.
