Question

Explain what is meant by `sp^3` hybridization?

Answer 1

`sp^3` hybridisation is when the `2s` and `2p` orbitals of an atom merge or hybridise, allowing a carbon atom to form four bonds.

Explanation:

The electronic configuration of a carbon atom is `1s^2 2s^2 2p_x^1 2p_y^1`.

There are two lone electrons here, meaning that carbon should only actually be able to form two bonds.

However, a little bit of energy can be added which promotes an electron from the `2s` orbital, which makes the carbon into an excited state. The electronic configuration is now `1s^2 2s^1 2p_x^1 2p_y^1 2p_z^1`, which has four lone electrons, so can form four bonds.

The problem now is that the electrons are in different subshells. The bonds in methane are symmetrical, and you don't get the same bonds if you have different subshells, so the orbitals hybridise.

Rather than being in `s` and `p` orbitals, they merge into `sp^3` orbitals, which look like half a `p` orbital and move apart as far as possible - about `109.5^o`.

These orbitals can then react with four hydrogen atoms to form methane. The sigma bonded orbitals are the same shape but have a hydrogen nucleus (a proton) in their lobe. The reaction looks like this