Which of the following best describes hybridization?

Hybridization is a crucial concept in understanding molecular structure and bonding in chemistry. The process involves the combination of atomic orbitals to form new hybrid orbitals that can accommodate the bonding electrons in a molecule. These hybrid orbitals have different shapes and energy levels than the original atomic orbitals, allowing for more effective overlap with orbitals from other atoms during bond formation.

In molecular geometry, hybridization explains why certain molecules adopt particular shapes. For instance, in methane (CH₄), the carbon atom undergoes sp³ hybridization, resulting in four equivalent hybrid orbitals that form sigma bonds with hydrogen atoms, giving the molecule a tetrahedral shape.

Understanding hybridization allows chemists to predict and explain the bonding behavior of molecules. The other options provided, while related to atomic structure and bonding, do not accurately describe hybridization. Mixing of electron shells does not define the concept, nor does ionization pertain to the formation of hybrid orbitals. Similarly, forming ionic bonds involves the complete transfer of electrons between atoms rather than the blending of orbitals to create a shared bonding scenario.