Here's why:

* Hexane's Structure: Hexane is a hydrocarbon with the formula C6H14. It has a linear chain of six carbon atoms, each bonded to two hydrogen atoms.

* Carbon's Bonding: Carbon has four valence electrons. In hexane, all of these electrons are used to form single covalent bonds (sharing electrons) with other carbon atoms and hydrogen atoms.

* Hydrogen's Bonding: Hydrogen has one valence electron. In hexane, all of these electrons are used to form single covalent bonds with carbon atoms.

Since all the valence electrons in hexane are involved in covalent bonding, there are no unshared (also called lone) electron pairs on any of the atoms.