<P> The noble gases ( historically also the inert gases ) make up a group of chemical elements with similar properties ; under standard conditions , they are all odorless , colorless , monatomic gases with very low chemical reactivity . The six noble gases that occur naturally are helium ( He ) , neon ( Ne ) , argon ( Ar ) , krypton ( Kr ) , xenon ( Xe ) , and the radioactive radon ( Rn ) . Oganesson ( Og ) is variously predicted to be a noble gas as well or to break the trend due to relativistic effects ; its chemistry has not yet been investigated . </P>
<P> The noble gases ( historically also the inert gases ) make up a group of chemical elements with similar properties ; under standard conditions , they are all odorless , colorless , monatomic gases with very low chemical reactivity . The six noble gases that occur naturally are helium ( He ) , neon ( Ne ) , argon ( Ar ) , krypton ( Kr ) , xenon ( Xe ) , and the radioactive radon ( Rn ) . Oganesson ( Og ) is variously predicted to be a noble gas as well or to break the trend due to relativistic effects ; its chemistry has not yet been investigated . </P>
definition of noble gases on the periodic table
definition of noble gases on the periodic table
odorless , colorless , monatomic gases with very low chemical reactivity
odorless , colorless , monatomic gases with very low chemical reactivity