Question

Lewis octet rule .............

Answer 1

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1. Atom having 8 electrons in outermost shell are stable and never combined while those which has less than 8 electrons they combine with other.
2. After combining they complete their electron in the outermost shell.

Stable atoms are :-

• Hydrogen .
• Helium .
• lithium

Non stable atoms are :-

• Sodium
• Magnesium
• Aluminium

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.

$\rule{150}{2}$

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

$\rule{200}{2}$

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.