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

1 Answer
May 25, 2018

Answer:

D) #1# lone pair.

Explanation:

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

  1. The total number of electrons in #XeF_6# is #8+(7xx6)=50# electrons.
  2. #Xe# will be the central atom. So, let's just connect #Xe# and #F# atoms with a single bond each.
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  3. 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.
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  4. 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!)
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So, there are #2# electrons on #Xe#—which is #1# pair.