Question

What is octet rule? How do you appreciate the role of octet rule?

Answer 1

Answer:

Explanation:

Octet rule – it states that atoms of elements are stable with 8 electrons in their outermost shell and they tend to undergo chemical changes ( losing or gaining electrons ) to get this structure.

Elements after these chemical changes attain noble gas configuration. Chemically active elements don’t have 8 electrons in their outermost shell and that’s why they lose or gain electrons to obtain stable octet structure.

Atoms having more than 4 electrons and less than 8 electrons, already in their outermost shell, tend to gain electrons thereby becoming negatively charged (anions). Atoms having less than 4 electrons and more than 0 electrons, already in their outermost shell, tend to lose electrons thereby becoming positively charged (cations). The ultimate result of this is obtaining octet in outer most shell.

Answer 2

Answer :

Octet rule: Atoms of elements combine with each other in order to complete their respective octets so as to acquire the stable gas configuration.

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Significance: It helps to explain why different atoms combine with each other to form ionic compounds or covalent compounds.

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Limitations of Octet rule:

(1). According to Octet rule, atoms take part in chemical combination to achieve the configuration of nearest noble gas elements. However, some of noble gas elements like Xenon have formed compounds with fluorine and oxygen. For example: XeF2, XeF4 etc.

Therefore, validity of the octet rule has been challenged.

(2). This theory does not account for shape of molecules.