discuss carefully the electronic configurations of NO,CO,HF and HCl
Answers
Answer:
The Cl electrons residing up to 3s orbital (1s, 2s, 2px,2py,2pz,3s) are largely stabilized than H electron in 1s orbital and therefore they cannot mix and form bond. The 3p electrons of Cl have comparable energy with the H electron and therefore are allowed to mix. However, since 3px and 3py orbitals have different symmetry than that of 1s orbital (if you consider z-axis as the internuclear axis), the only possible mixing situation is the sigma type overlap between the 1s orbital of H and 3pz orbital of Cl. Note that both these orbitals are half filled and therefore allowed to form a bond. Therefore, the HCL molecule has 8 pairs (1s, 2s, 2px,2py,2pz,3s,3px and 3py) of non-bonding (nb) electrons and one bonding (sigma) orbital having two electrons. The sigma antibonding orbital will be empty. The nb electrons would reside on Cl atom. Since the electronegativity of Cl is greater than the H atom, therefore the sigma bonding electrons will lie closer to Cl than the H.
why carefully?
HF -In hydrogen fluoride (HF), the hydrogen 1s orbital can mix with the fluorine 2p orbital to form a sigma bond because experimentally, the energy of 1s of hydrogen is comparable with 2p of fluorine. The HF electron configuration reflects that the other electrons remain in three lone pairs and that the bond order is one.
