Video Transcript
Butane, C4H10, has the structural
formula shown. What is the hybridization of the
carbon atom in the butane? (A) sp3, (B) sp, (C) sp2, or (D)
sp3d.
Orbital hybridization is the
concept of mixing atomic orbitals into new and different types of hybrid
orbitals. Carbon atoms have the He 2s2 2p2
electron configuration. And it would be reasonable to
assume that the 2s and 2p atomic orbitals have different interactions with
covalently bonded hydrogen atoms in molecules like butane, considering their
different energies and shapes. But experimental data suggests this
is not the case at all.
The 2s and 2p orbitals tend to
mathematically combine to form four hybrid sp3 bonding orbitals. They all make equivalent bonds with
the 1s orbital electrons of adjacent hydrogen atoms and spread out equally in
three-dimensional space. Let’s see how this hybridization
will occur.
This is carbon’s valence electron
configuration. Carbon has valence electrons in the
2s and 2p atomic orbitals. The first step in orbital
hybridization is the promotion of an electron. For carbon, a 2s electron is
promoted to an empty 2p orbital, which puts carbon in an excited state. Now, carbon has four unpaired
electrons in the 2s and 2p orbitals. These four unpaired electrons in
different orbitals are mixed together to create four identical orbitals of the same
energy level. These four identical orbitals are
neither s orbitals nor p orbitals. They are sp3 hybrid orbitals.
Therefore, option (A), sp3, is the
correct answer.
