Question

Discuss the importance of the $\mathbf{c}\mathbf{-}\mathit{c}$ and Si-Si bond strengths and of$\mathit{\pi }$ bonding to the properties of carbon and silicon.

Short answer

The atom of carbon double bonds is stronger and hence less reactive than silicon atoms' double bonds.

Step-by-step solution

Definition of bond

A chemical bond is an atom-to-atom attraction. This attraction can be explained by differences in the behaviour of atoms' outermost or valence electrons

Explain the importance of C-C and Si-Si bond strengths

As moved along a column, the bonds between similar atoms normally weaken.

The C-C single bond, for example, is stronger than the Si-Si single bond.

This is due to the fact that as you progress down a column, bonded atoms get bigger, and the area between them occupied by bonding electrons shrinks proportionately.

One sigma bond and one pi bond make up a double bond.

Each carbon atom in ethylene, for example, contains three$s{p}^2$ orbitals and one orbital.

The three$s{p}^2$ orbitals are in a plane with around${120}^{°}$ angles.

This plane is perpendicular to the orbital. Two of the$s{p}^2$ orbitals overlap when the carbon atoms approach each other, forming a sigma bond. The two orbitals approach (again in the same plane) at the same moment, forming a pi bond.

Because the orbitals must stay parallel for maximal overlap, rotation around the central bond is not conceivable.

Each silicon in the double bond forms sigma bonds with three atoms using its three$s{p}^2$ hybrid orbitals.

Explain the importance of pi bond

The pi bond is formed by the un-hybridized$3p$ atomic orbitals that lie perpendicular to the plane established by the axes of the three$s{p}^2$ hybrid orbitals. This bond is half on one side and half on the other, and it is outside the main Si-Si axis.

Because it requires breaking the pi link, rotation around the silicon-silicon double bond is not constrained.

When it comes to double bonds between silicon atoms, the overlap of$3p$ and$3s$ orbitals is less than that of$2p$ and$2s$ orbitals in carbon.

As the energy difference between the$ns$ and$np$ orbitals of a silicon atom is bigger than that of a carbon atom, this is the case.

Silanes have much greater reactivity due to weaker double bonds in silicon compounds compared to double bonds between carbon atoms.

This are tough to separate because of this, but alkenes are abundantly accessible organic molecules.