The atomic radii of noble gases increase with the increase in atomic number. The new shells are added and hence electron cloud expands. Hence the atomic size increases down the group.
The outermost orbits of inert gases have a noble configuration. They possess very high ionization energies. The ionization energy of noble gas is highest among the members of the same period.
|Elements||Atomic radii (pm)||Ionization energy KJ/mol|
The outermost orbits of noble gases have a noble configuration. Therefore they are unable to take an extra electron. That’s why the electron affinity of inert gases is almost zero.
The noble gases exist as single atoms. Due to very high ionization energies and also have almost zero electron affinity, inert gases are not capable to combine amongst themselves. And exist as a single atom.
Force of attraction
The noble gases can be liquefied which indicates that the presence of some force of attraction between inert gases. But it is very weak as inert gases have a complete octet.
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The liquefication of noble gases is very difficult because very weak Van der Waals’ forces of attraction exist between them.
Also, van der Waal’s force of attraction increases from helium to xenon and the ease of liquefication increases in the same way.
Solubility in water
These gases are slightly soluble in water. However, solubility increases with increase in atomic number.
High ionization energy, almost zero electron affinity, weak force of attraction, less soluble in the water, difficult to liquefy are the properties of noble gases