Overlap reasoning

[105907609]

I know that pi bonds have side on overlap and sigma bonds have top overlaps, but I do not quite understand why. I know it is the orbitals overlapping but I do not understand the scientific reasoning behind why these are different and what exactly is happening.

[Destiny Caldwell 3J]

sigma (σ) and pi (π) bonds involves considering the nature of atomic orbitals and the geometry of molecular orbitals. The distinction between sigma and pi bonds lies in the orientation and nature of the overlapping atomic orbitals. Sigma bonds involve head-on overlap along the internuclear axis, maximizing orbital overlap. Pi bonds involve side-to-side overlap of parallel p orbitals, creating a nodal plane along the axis, which leads to weaker bonding compared to sigma bonds.For example, in a molecule with a double bond such as ethene, C2H4, there is a sigma bond resulting from the head-on overlap of two sp2 hybridized orbitals, and there is also a pi bond resulting from the side-to-side overlap of two parallel p orbitals.

[Reva Patel 2F]

It has to do with the geometry of pi bonds and sigma bonds. I've attached two pictures below to show sigma bonds and pi bonds. Overall, sigma bonds consist of the s orbital overlapping with an s orbital, or an s and p overlap, which both can happen at the tops. P orbitals can only overlap side-by-side.