-they are all odorless, colorless, monatomic gases with very low chemical reactivity.
-they’re all found in group 18 on the periodic table, all the way on the far right.
-they are the only elements that are unable to form compounds.
I think the the state <span>of the air in an isolated room is completely specified by the temperature and the pressure. Since it is isolated, the volume would be the same as the room. Gas is specified by temperature, pressure and volume. Having the values for pressure and temperature then the gas is completely specified. Hope this answers the question.</span>
Because just like compounds, the table of chemicals can be looked at as having all the different pieces of it. So the different chemicals are the different "elements" to the periodic table.