Question

What are the number of lone pairs of electrons on ${\mathrm{SF}}_4,{\mathrm{CF}}_4\mathrm{and}{\mathrm{XeF}}_4$?

Answer 1

Lone pair:

• It is a pair of electrons that is present in the valence shell which does not participate in the bonding and is sometimes also known as non-bonding pair.

Sulfur tetrafluoride $\left({\mathrm{SF}}_4\right)$:

• The total number of valence electrons in ${\mathrm{SF}}_4$ is $34$.
• The hybridization of this molecule is ${\mathrm{sp}}^3\mathrm{d}$. Thus, it has a see-saw geometry with one lone pair of electrons.
• The sulfur atom has one lone pair of electrons with four covalent bonds with fluorine atoms.

Carbon tetrafluoride $\left({\mathrm{CF}}_4\right)$:

• Carbon tetraflrouide has $32$ valence electrons.
• The hybridization of this molecule is ${\mathrm{sp}}^3$. Thus, it has a tetrahedral geometry.
• There are four bond pairs with no lone pairs on central atom, carbon in this molecule.
• Each fluorine atom has 3 lone pairs on it.

Xenon tetrafluoride $\left({\mathrm{XeF}}_4\right)$:

• Xenon tetrafluoride has $36$ valence electrons.
• The hybridization of this molecule is ${\mathrm{sp}}^3{\mathrm{d}}^2$. Thus, it has a square planar geometry.
• This molecule has $4$ bond pairs and $2$ lone pairs of electrons around the central atom, xenon.