are bond formation always exothermic
As you said, it's true that breaking bonds always absorbs energy. But breaking bonds is just halfway through for a chemical reaction. Forming new ones releases energy. The difference within determines a chemical reaction endothermic or exothermic. For ATP hydrolysis, the bonds within an ATP and a water molecule break, which absorbs energy, as you might think. Then the new bonds formation to form an ADP and a phosphate releases a lot of energy. An exothermic reaction is a chemical reaction that releases energy by light or heat. It is the opposite of an endothermic reaction. Expressed in a chemical equation: reactants → products + energy. Energy is always released when bonds are formed, but the overall reaction is only exothermic if the energy released in forming new bonds is greater than the energy required to break the original ones. Bonds do store potential energy. It requires energy to break the bonds. Energetics of Ionic Bond Formation. The formation of ionic compounds (like the addition of sodium metal and chlorine gas to form NaCl) are usually extremely exothermic. The loss of an electron from an element: Always endothermic (takes energy to strip the e' from the atom) Na(g) -> Na+(g) + 1e- DH = 496 kJ/mol. Therefore, energy is released when a bond forms. Chemical reactions occur, and bonds form, because the products will always be a lower total energy (Gibbs free energy) than the reactants. Bond breaking is endothermic. Bond making is exothermic. An exothermic reaction is a chemical or physical reaction that releases heat. It gives net energy to its surroundings. That is, the energy needed to initiate the reaction is less than the energy released. When the medium in which the reaction is taking place gains heat, the reaction is exothermic. The change in enthalpy is negative in exothermic processes, because energy is released from the system into its surroundings. Generally, a positive change in enthalpy is required to break a bond, while a negative change in enthalpy is accompanied by the formation of a bond. In other words, breaking a bond is an endothermic process, while the formation of bonds is exothermic. Bond Enthalpy or Dissociation Energy. Likewise it takes energy to break a bond. Therefore, energy is released when a bond forms. Chemical reactions occur, and bonds form, because the products will always be a lower total energy (Gibbs free energy) than the reactants. Therefore: Bond breaking is endothermic. Bond making is exothermic. No. It is exothermic. Covalent and any other kind of bonds owe their stability to the fact that the total energy of the bonded atoms is lower than the sum of energies of the unbounded atoms. The excess energy is released, thus determining the exothermic character of bond formation. If the formation of a bond were accompanied by an increase of energy,the bond just wouldn't form at all, as in the case of two atoms of helium. I hope this will solicit more questions. If energy is stored in chemical bonds, and bond formation is always an exothermic process, doesn't that imply that bond formation both stores and releases energy? How is this possible? I'm clearly not understanding some basic tenet of chemistry. For example, H+ and OH- neutralize to form H2O.
Yes, it is always an exothermic process.