Question

What are the salient features of the valence bond theory?

Answer 1

1. When two atoms' half-filled orbitals overlap, they form a covalent bond.
2. The two electrons with opposing spins occupy the overlapping orbitals. For example, when H2 is created, the two electrons from two hydrogen atoms link up and occupy the overlapped orbitals.
3. The strength of a covalent bond is determined by the extent of atomic orbital overlap. The greater the overlap, the more energy is released, and the stronger the bond formed.
4. Each atomic orbital has a specific orientation (with the exception of spherical orbitals); therefore, orbital overlap occurs in the direction that maximizes overlap.
5. Bonds are classed as σ or π covalent bonds based on their overlap.
6. A sigma bond (σ) is formed when two atomic orbitals overlap linearly along an axis. This overlap is also known as “axial overlap.”
7. When two atomic orbitals overlap sideways, the resulting covalent link is known as a pi bond.