MediumChemistryHigh School (11–12)Chemical Bonding › Shapes of Molecules and HybridisationConceptual

Xenon is a noble gas with 8 outer electrons, yet it forms XeF₂, XeF₄ and XeF₆.

Try it on paper first. A hint, the key idea and the worked solution are here when you need them.

Xenon is a noble gas with $8$ outer electrons, yet it forms $\text{XeF}_2$ , $\text{XeF}_4$ and $\text{XeF}_6$ . Find the electron pairs and lone pairs on xenon in each, and predict the shapes of $\text{XeF}_2$ and $\text{XeF}_4$ .

Need a reminder? The key ideaShow

VSEPR theory: count the electron pairs on the central atom as $\dfrac{V + M \pm q}{2}$ . Here $V$ is its outer electrons, $M$ its singly bonded atoms and $q$ the charge, added for an anion. Pairs spread out: 2 linear, 3 trigonal planar, 4 tetrahedral, 5 trigonal bipyramidal, 6 octahedral. Lone pairs repel more than bonding pairs. The shape names only the positions of the atoms. With five pairs, lone pairs take equatorial positions.

The worked solution

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Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.

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