The properties of the noble ( inert ) gases
The inert gases are the elements in which the outermost electron shells are completely filled with the electrons , so they don’t participate in any chemical combination in the ordinary conditions .
The noble gases do not form positive or negative ions in the ordinary conditions , The elements of the atoms of which all the shells completely filled are called the inert gases or the noble gases or the rare gases .
Helium ( He ) , Neon ( Ne ) , Argon ( Ar ) , Krypton ( Kr ) , Xenon ( Xe ) and Radon ( Rn ) are the inert gases , The noble gases make a group of chemical elements with similar properties under standard conditions .
The noble gases are odorless , colorless , monoatomic gases with very low chemical reactivity , and each molecule consists of one single atom ( monoatomic ) .
The noble gases have weak interatomic force , They have low melting and boiling points , they are all monoatomic gases under the standard conditions , The noble gases are located in the far right column of the periodic table , they are in group ( 0 ) or group ( 18 ) .
They have a valence of zero , their atoms can not combine with other elements to form compounds , The noble gases have full valence electron shells , They are stable and do not tend to form chemical bonds .
The noble gases are commonly used in lighting because of their lack of chemical reactivity , and they glow in distinctive colors when they used inside gas-discharge lamps such as neon lights .
Some noble gases have direct application in medicine , and the noble gases are used in the excimer lasers .