Understanding Chemical Bonding: Why Last Sublevel Electrons Matter

[scientifico]

hello, to preview chemical bonds must be considered only the electrons in the last sublevel and not the electrons in all the level?
for example my book talking of carbon sp hybridation say that we shouldn't expect it make 4 bounds but only 3, why if the carbon need exactly 4 electron to complete the level?

thanks!

 

[Borek]

If your book really states sp hybridized carbon should make three bonds only, you should throw the book away.

http://en.wikipedia.org/wiki/Valence_electron

 

[ZealScience]

What do you mean? Carbon is usually a sp3 hybrid. Thus it must make four bonds. You also said that you need to consider the outer sublevel. What do you mean?

 

[Borek]

Carbon is usually a sp3 hybrid. Thus it must make four bonds.

While in a way it can be true that sp³ is the most common carbon hybridization, it doesn't matter. When it is sp or sp² it makes four bonds as well.

 

[scientifico]

Why in Wikipedia i read The valence bond theory would predict, based on the existence of two half-filled p-type orbitals, that C forms two covalent bonds ?
According to the normal model Carbon need 4 electrons to complete the last level so is it wrong use this model?
Do the bond are formed ONLY in the more external half-filled orbitals ?

thank you