Question

Question: The most common type of exception to the octet rule are compounds or ions with central atoms having more than eight electrons around them.SF₄ ,CIF₃ , and Br₃^2- are examples of this type of exception. Draw the Lewis structure for these compounds or ions. Which elements, when they have to, can have more than eight electrons around them? How is this rationalized?

Short answer

Answer

Phosphorus pentachloride (PCI₅ ) and sulphur hexafluoride (SF₆ ) are two compounds that stray from the octet rule by having more than 8 electrons surrounding the core atom.

Step-by-step solution

Hypervalent compounds

Main group elements that make more bonds than expected by the octet rule are known as hypervalent compounds, and they have a 'expanding octet,' which means that there are more than eight electrons surrounding one atom.

Elements with 8 electrons

Some elements are capable of extending the octet rule by employing the d-orbitals found in the third main energy level and beyond. Elements that can form an extended octet are sulphur, phosphorus, silicon, and chlorine.

Lewis Structure of the elements

Example of elements with 8 electrons

Phosphorus pentachloride ( PCI₅) and sulphur hexafluoride ( SF₆) are two compounds that stray from the octet rule by having more than 8 electrons surrounding the core atom.