What is onan unshared pair or nonbonding pair?

An unshared pair, or nonbonding pair, refers to a pair of valence electrons that are not involved in bonding with other atoms. These electrons are localized on a single atom and play a key role in determining the atom's geometry and reactivity. In molecular structures, nonbonding pairs can influence the shape of the molecule and the angles between bonded atoms, often leading to distortion from ideal geometries.