SP3 Hybridization in Ammonia

[alishehzad]

Hello...

I have a small conceptual problem. As far as i know, hybridization occurs when electrons prefer to live in different orbitals with same spin rather than same orbitals with different spin.

As far as hybridization in Carbon atom is concerned, it takes place because there are 2 electrons in 2S subshell ........ and 2 in 2P subshell i.e. Px = 1 , Py = 1 , Pz = 0

That is why one of the two electrons in 2S shifts to Pz and SP3 hybridization takes place.


However , the problem is with ammonia(NH3). The electronic configuration is 1 S2 , 2 S2 , 2 P3. i.e. Px = 1, Py = 1 , Pz = 1. There is no reason why the 2 S2 shuould over lap with 2P3 and form SP3 orbitals. BUT STILL THEY DO ... and form one lone pair and 3 Half filled bond pairs. (Which afterwards form covalent bonds with Hydrogen atoms)

My question is that why do the 2S2 electrons have to form SP3 orbitals with the 2P3 electrons, when they still remain the same i.e. 2P electrons in different orbitals with same spin and 2S electrons as a lone pair.

Do Reply ... thanks