Question

Explain the octet rule and give an example of how it is used.

Answer 1

Octect rule is very important in defining the stability of particular element or a molecule. If an atom posses eight electrons in valence shell giving it the same electronic configuration as a noble gas.

The chemical rule that states that atoms of low atomic number tend to combine or become ions so that they each have eight electrons in their valence shell, giving them the same electron configuration as a noble gas this is called as Octect rule.

we know that noble gases are very stable.

electron count can be done by using Lewis dot method.

consider CO₂

C electronic configuration is 1s²2s²2p²

in its excite state C = 1s²2s¹2p_x¹2p_y¹2p_z¹

O electronic configuration is 1s²2s²2p⁴

i.e., O = 1s²2s² 2p_x²2p_y¹2p_z¹

Carbon contains 4 electrons in its valence shell it requires still 4 electrons for octect. oxygen contains 6 electrons in its valence shell it requires two electrons for its octect. so one carbon atom and two oxygen atoms share their valence electrons and get paired in such a way that each atom possess eight electrons each.

we can observe that C electrons were represented in black that is four valence electrons of carbon, oxygen contains 6 valence electrons represented in red color. now each atom shares their electrons and each atom possess eight electrons as shown and gets stabilized.

note: Any bond comprises 2 electrons whether it can be ionic covalent or whatever...

in the structure of CO₂ four electron comprises two bonds one is sigma bond and another is a pi bond between carbon and oxygen so finally, the structure of CO₂ is as given below. It posses a linear structure.