What is the difference between a sigma and pi bond? Use your answer to explain why there is fixed rotation about the C=C bond.

What is an atomic orbital? Electrons are not entirely confined within the atom. An orbital is the defined space around the central nucleus of an atom where electrons are predicted to be. Each can contain a maximum of two electrons. There are different types of electron orbital that we can come onto later with varying energy levels (s,p,d,f) . Again the combination of orbitals is determined by the element of the atom.(Draw S orbital and P orbital)What is a sigma bond? Its a form of chemical covalent bond between atoms. It consists of the overlap between two s atomic orbitals of the atoms. This is the type of covalent bond found in single bonds (when molecules are written in their displayed formulae these are denoted by single lines.)What is a pi bond? Its a form of covalent bond that occurs between atoms. It involves the overlapping of two p orbitals of the bonding atoms. Denoted by a double line (=) between atoms in their dispalyed formulae.What is a double bond?When there is a sigma as well as a pi bond between the atoms. Both overlap of the p and s orbitals. C=C Double bond is the defining functional group that occurs in alkenes.Why is there a fixed rotation about this bond?The overlap of the p orbitals doesnt allow for much rotation because the orbital planes areabove and below the planes of atoms. Where as a single bond has its orbitals in one plane in line with the atoms so rotation is free.Think of a single bond is being like to two boards overlapping that are nailed together with one nail. A double bond is more like two boards nailed together with two nails. In the first case you can twist the boards, while in the second case you cannot twist them.