A double bond in an alkene is a covalent bond between two carbon atoms that involves the sharing of four electrons, instead of the two electrons shared in a single bond. This double bond consists of two parts: 1. A sigma bond (σ bond): This is a strong bond formed by the direct overlap of atomic orbitals along the axis connecting the two carbon nuclei. 2. A pi bond (π bond): This is a weaker bond formed by the sideways overlap of unhybridized p orbitals above and below the axis of the sigma bond. The presence of the pi bond makes the double bond shorter, stronger, and more reactive than a single bond. It also restricts rotation around the carbon-carbon axis, leading to cis-trans isomerism in some alkenes. Last one for today! Send it over.