What are the periodic trends of the group noble gases?

The properties of the noble gases can be well explained by modern theories of atomic structure: their outer shell of valence electrons is considered to be "full", giving them little tendency to participate in chemical reactions, and it has only been possible to prepare a few hundred noble gas compounds. The melting and boiling points for each noble gas are close together, differing by less than 10 �C (18 �F); consequently, they are liquids over only a small temperature range.