Final answer:
The exceptions to the Lewis octet rule among the given options are BeF2 and SF4, because BeF2 has an incomplete octet, and SF4 has an expanded valence shell.
Step-by-step explanation:
The exceptions to the Lewis octet rule are molecules or ions that do not follow the rule that atoms share electrons so each atom has eight electrons in their valence shell. The exceptions include molecules with incomplete octets, those with odd numbers of electrons, and those with expanded valence shells.
Examining the options given:(II) BeF2 and (III) SF4 are exceptions to the octet rule. BeF2 is an example of a molecule with an incomplete octet, as beryllium commonly forms compounds with only four electrons in its valence shell. SF4 is an example of a molecule with an expanded valence shell, as sulfur can have more than eight electrons in its valence shell due to the presence of d orbitals. While CO2 and SO3 adhere to the octet rule, PCl3 fits the rule as well since phosphorus achieves an octet through its three covalent bonds with chlorine and a lone pair on phosphorus itself.