In
chemistry, a
lone pair refers to a pair of
valence electrons that are not shared with another atom and is sometimes called a
non-bonding pair. Lone pairs are found in the outermost
electron shell of atoms. They can be identified by using a
Lewis structure. Electron pairs are therefore considered lone pairs if two electrons are paired but are not used in
chemical bonding. Thus, the number of lone pair electrons plus the number of
bonding electrons equals the total number of valence electrons around an atom.