Question

Which of the following does not exist?
A.$\text{XeO}{{\text{F}}_{\text{4}}}$
B.$\text{Ne}{{\text{F}}_{\text{2}}}$
C.$\text{Xe}{{\text{F}}_{\text{2}}}$
D.$\text{Xe}{{\text{F}}_{6}}$

Answer 1

The noble gases are generally unreactive except for the higher members of the group because they have a fulfilled octet and duplet configuration. Xenon is the only noble gas which forms compounds.

Complete answer:
The noble gases are the members of group 18 family and they are called noble due to their non-active or inert nature. They are helium, neon, argon, krypton, xenon, and radon. The reason for this inactivity is that the noble gases have attained the duplet or octet configuration. Hence they have negligible tendency to accept electrons. But there are some relaxations in case of the higher members of the group as they have valence ‘f’ and ‘d’ orbitals that can be expanded to take up more electrons. So they accept electrons from donor atoms to form different compounds. The examples of these elements are xenon mainly and krypton to lesser extents.
Neon belongs to the second period of the periodic table and these are two orbitals in its valence orbit which are totally filled with electrons with no more space to accommodate extra electrons.

Hence, the compound neon fluoride or$\text{Ne}{{\text{F}}_{\text{2}}}$is not possible. The correct answer is option B.
Note:
As the xenon belongs to the 5th period of the periodic table, there is the vacant 5d and 5f orbital that are there to accommodate the extra electrons. But these orbitals have very high energy so they try to accept electron pairs from ligands that are small and compact as these lead to stronger bonds.