Intramolecular Force and Potential Energy

Bond Length and Bond Energy

• The distance between two covalently bonded hydrogen atoms is about 74 picometers.

• If your were to decrease the distance between these atoms, the potential energy would increase due to increased attractive forces and having to put energy in, leading to a more stable configuration.

• Conversely, if the distance were to increase, the potential energy would rise, resulting in a less stable configuration as the repulsive forces between the atoms would dominate.

• Bond energy is the energy (typically in kJ/mol) required to dissociate atoms.

• The smaller the atoms and the higher the order of bonds (double bond, triple bond) the greater the bond energy.

Lattice Energy

• In chemistry, a lattice structure refers to a 3-dimensional structure of ions in a repeating form.

• Lattice energy is similar to bond energy, but it is the energy needed to pull ions apart, completely (kJ/mol).

• Similarly to bond energy, the smaller the ions the stronger the lattice energy, due to Coulomb’s law.