Question

How many lone pairs are on the central atom in ${\text{XeO}}{{\text{F}}_{\text{2}}}$
?

Answer 1

Hint: We know that lone pair is a pair of valence electrons that is not used in formation of covalent bonds. And this electron pair is sometimes known as a nonbonding pair or unshared pair. Here, to know the number of lone pairs on the central atom, first we have to know the valence electron of Xe.

Complete step by step answer:
The given compound is a compound of xenon, that is, ${\text{XeO}}{{\text{F}}_{\text{2}}}$. Here, the xenon is bonded to one oxygen atom and two fluorine atoms.

We know that xenon is a noble gas that belongs to the group 18 of the periodic table. Its atomic number is 54. The electronic configuration of xenon is $\left[ {{\text{Kr}}} \right]4{d^{10}}5{s^2}5{p^6}$. So, the number of valence electrons of xenon is 8.

Now, we discuss the covalent bonding in ${\text{XeO}}{{\text{F}}_{\text{2}}}$. Out of 8 valence electrons, two are shared with the oxygen atom to form double covalent bond and one electron is shared with two fluorine atoms each to form two Xe-F single covalent bonds. So, four electrons remain unshared on the xenon atom.

Let’s understand with the help of the diagram.

So, the number of lone pairs in ${\text{XeO}}{{\text{F}}_{\text{2}}}$ is 2.


Note: It is to be remembered that all elements belong to group 18 are termed as noble gas. These elements have a complete octet of valence shell, so they are inert in nature. The best characterized compounds are formed due to the reaction of xenon with oxygen and fluorine under certain conditions. Some example of xenon compounds are ${\text{XeO}}{{\text{F}}_{\text{2}}}$, ${\text{Xe}}{{\text{O}}_{\text{2}}}{{\text{F}}_{\text{2}}}$ etc.