Hybridisation of atomic orbitals refers to which process?

• A. Mixing of atomic orbitals to form new, equivalent orbitals
• B. Ionisation of atoms
• C. Formation of ionic bonds
• D. Delocalisation of electrons in metals

Answer: (A)

Hybridisation is the mixing of atomic orbitals on an atom to produce new, equivalent orbitals with specific orientations. By combining s and p (and sometimes d) orbitals, orbitals such as sp, sp2, and sp3 are formed. These hybrid orbitals are better suited for overlapping with orbitals on other atoms to make covalent bonds, and their directional nature explains the observed bond angles and shapes in molecules (for example, carbon using four sp3 hybrids to bond to four hydrogens in methane gives a tetrahedral geometry). This is a way to describe bonding using overlapping orbitals, not processes like removing electrons, forming ionic bonds by electron transfer, or delocalisation of electrons in metals.