The stronger bond will be formed by the orbital that is more directionally concentrated.

- In order to understand why the more directionally concentrated orbital forms a stronger bond, we need to consider the concept of orbital overlap.
- Orbital overlap occurs when two atomic orbitals come into close proximity and their electron densities merge, resulting in the formation of a bonding molecular orbital.
- The degree of orbital overlap determines the strength of the bond.

Orbital Directionality:
- The directionality of an orbital refers to the spatial orientation of its electron density.
- Some orbitals are more directional, meaning their electron density is concentrated in a specific region of space.
- Other orbitals are less directional and have electron density distributed more evenly.

Effect on Bond Strength:
- When two orbitals with identical stability but different directionality come into close proximity, the more directionally concentrated orbital will have a stronger bond.
- This is because the concentrated electron density of the orbital allows for a greater degree of orbital overlap with the other orbital.
- The greater the overlap, the stronger the bond formed between the two atoms.

- On the other hand, less directionally concentrated orbitals have electron density that is more evenly distributed.
- As a result, the overlap between these orbitals is less efficient, leading to a weaker bond.

Example:
- For example, consider the bonding between two hydrogen atoms in a hydrogen molecule (H2).
- Each hydrogen atom has a 1s orbital, which is spherically symmetric and less directionally concentrated.
- When the two hydrogen atoms approach each other, the 1s orbitals overlap, but the overlap is not as efficient due to the less directional nature of the orbitals.
- As a result, the bond formed in H2 is weaker compared to other molecules with more directionally concentrated orbitals, such as the sigma bond formed between two sp hybridized carbon atoms in ethyne (C2H2).

Conclusion:
- In conclusion, the more directionally concentrated orbital forms a stronger bond due to the greater degree of orbital overlap that can occur with other orbitals.