How many lone pairs of electrons are on the $Xe$ atom in $XeF_6$ ? A) 0 B) 3 C) 2 D) 1

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Answer 1 · 2018-05-25T03:25:40

D) $1$ lone pair.

First, let's draw the Lewis Structure for $XeF_6$ :

The total number of electrons in $XeF_6$ is $8+(7xx6)=50$ electrons.
$Xe$ will be the central atom. So, let's just connect $Xe$ and $F$ atoms with a single bond each.
me
We have $50-12=38$ electrons left to draw on.
This means that we have enough electrons to not need double bonds and complete the octet for $F$ using lone pairs.
me
However, we still have $38-36=2$ electrons left to use.
These electrons will need to be placed on $Xe$ , since $Xe$ , having its valence electrons in the $5p$ orbital, have empty $5d$ , $4f$ , and $5f$ orbitals—allowing it have more electrons than an octet.
(For more information on exceeding octets, check out this article on Wikibooks!)
me

So, there are $2$ electrons on $Xe$ —which is $1$ pair.

How many lone pairs of electrons are on the XeXe atom in XeF_6XeF_6? A) 0 B) 3 C) 2 D) 1