Flexi Says: The formation of a chemical bond results in a decrease in potential energy. Consequently, breaking a chemical bond requires an input of energy. Bond energy is the energy required to break a covalent bond between two atoms. High bond energy means that a bond is strong and the molecule that contains that bond is likely to be stable and less reactive and it will be difficult to break such bonds. More reactive compounds will contain bonds that have generally lower bond energies and are easier to break.