Final answer:
In cumulene, orbital overlaps involve sigma bonds, formed by end-to-end overlaps, and pi bonds, created by side-by-side overlaps. Sigma bonds concentrate electron density along the internuclear axis, while pi bonds distribute it above and below the plane of the nuclei.
Step-by-step explanation:
The types of orbital overlap that occur in cumulene involve sigma (σ) bonds and pi (π) bonds. Cumulene molecules contain a series of double bonds that are consecutively joined together. In cumulenes, sigma bonds are formed by the end-to-end overlap of orbitals, such as in hydrogen (H₂), hydrogen chloride (HCl), and chlorine (Cl₂), where the electron density is concentrated along the internuclear axis. On the other hand, pi bonds are formed by the side-by-side overlap of p orbitals, with the electron density distributed above and below the plane of the nuclei of the bonding atoms.
The identification of sigma and pi bonds was exemplified in various figures where sigma bonds form from the overlap of two s orbitals, the overlap of an s orbital and a p orbital, and the end-to-end overlap of two p orbitals. Additionally, a pi bond is observed as a second bond in double bonds between carbon atoms, extending above and below the plane of the molecule.