Question

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

Answer 1

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.
   
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.
   
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!)
   

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