There are two main types of covalent bond breakage. In homolytic breakage (as in Table 9.2, p. 371), each atom in the bond gets one of the shared electrons. In some cases, the electronegativity of adjacent atoms affects the bond energy. In heterolytic breakage, one atom gets both electrons and the other gets none; thus, a cation and an anion form.
(b) Use bond energy and any other data to calculate the enthalpy of reaction for the heterolytic cleavage of O₂.