Octet rule?

Question

What is the octet rule in chemistry

Answer 1

elements with 8 electrons in valence shell r stable atomic gases..

Answer 2

The octet rule is a simple chemical rule of thumb that states that atoms tend to combine in such a way that they each have eight electrons in their valence shells, giving them the same electronic configuration as a noble gas. This 8-electron configuration is especially stable because with 8 valence electrons, the s- and p-orbitals are completely filled (with 2 in the s-orbital, and 6 in the p-orbitals). Having completely filled orbitals provides increased stability due to something called "exchange energy."

The rule is applicable to the main-group elements, especially carbon, nitrogen, oxygen, and the halogens, but also the metals in the first two columns of the periodic table (but not to the transition metals in the middle of the periodic table). Note that the elements hydrogen (H) and helium (He) don't follow the octet rule, but rather the "duet" rule (2 electrons) because they don't have any p-orbital electrons.

In simple terms, molecules or ions tend to be most stable when the outermost electron shells of their constituent atoms contain eight electrons.

Answer 3

Octet rule means that to become fully stable each element should have 8 electrons in its outermost shell. Elements either gain/lose electrons to get 8 electrons in their outermost (valence) shell.

Similarly there is another called Duplet rule .. according to which each element has 2 electrons in its first shell

hope tht helps

Answer 4

The connection between the octet rule and the inert gases is what drives the importance of the octet rule.  Why do we say that having eight outermost electrons is stable?

The inert gases are those which do not form chemical bonds or very few bonds.  Chemical bonds form in order to get to a lower energy level where the electron arrangement is most stable.  Clearly, whatever arrangement the inert gases have must be particularly stable.  All inert gases (except He) have completely filled ns and np sublevels for a total of 8 outermost electrons.

We've can also see that many ions are isoelectronic with the inert gases meaning that they are particularly stable as well.  

And all of this with 8 outermost electrons, hence the octet rule.