Chemistry of Noble Gases
The group 18 consists of six elements namely helium, neon, argon, krypton, xenon and radon. These gases do not have any chemical reactivity at room temperature. That is why these gases are called as noble gases. Due to very low reactivity, these gases always occur in the Free State in the atmosphere.
General characterstics of Noble Gases:-
- All the noble gases have fully filled and stable electronic configurations. Except helium (having 2 valence shell in its shell), the atoms of all the noble gases have 8 electrons in their valence shell.
- The atomic size of noble gases increases as we go down the group.
- The enthalpy of ionization of noble gases is very high due to completely filled shells.
- As noble gases have stable electronic configurations, they have very less tendency to accept additional electrons. Thus, the value of electron gain enthalpy for noble gases is nearly zero.
- Their melting and boiling points are very low.
- Noble gases cannot be easily liquefied.
- These are slightly soluble in water.