What is duplet rule?

Is it like the 8 electron rule, but for the S shell - i.e Hydrogen? It means the Hydrogen atom must have 2 electrons to fill its outer shell and be in a stable bond. Like larger atoms which need 8 to fill their shells. It's why Hydrogen only forms one bond - because it needs just one more electron to fill its shell. Carbon on the other hand needs 4 bonds, beacause it needs 4 more electrons to be stable - thus giving it 8 in total. (2 in the s orbital and 6 in the p).

 

 

Is that what you meant - or have I completely missed the point:D?

I don't really get it.. Is it the same as octet rule? Which react to become stable?

Yes, I think that's what you mean - like the octet rule, but for smaller atoms like Hydrogen and Helium where their outer shell is the s orbital. So they need 2 electrons to fill the shell. The larger atoms need 8 because they have to fill the s-orbital (2 electrons) and the p-orbital (6 electrons) - thus 'octet' rule - 8 electrons.

Ah Ok, thanks..