Question

which of the following compounds demonstrates an exception to the octet rule?
c₂h₆
kcl
h₂o
sf₆

Explanation:

The octet rule states atoms tend to have 8 valence electrons. $\text{C}_2\text{H}_6$ (C: 4 bonds=8e⁻, H:2e⁻), $\text{KCl}$ (ionic, K⁺ and Cl⁻ each have 8e⁻), $\text{H}_2\text{O}$ (O:2 bonds+2 lone pairs=8e⁻) follow the rule. $\text{SF}_6$ has S bonded to 6 F atoms, giving S 12 valence electrons, violating the octet rule.

Answer:

SF₆