Edexcel A Level Chemistry:复习笔记1.4.7 Bond Length & Bond Strength

Bond Length & Bond Strength


Bond energy

  • The bond energy is the energy required to break one mole of a particular covalent bond in the gaseous states
    • Bond energy has units of kJ mol-1


  • The larger the bond energy, the stronger the covalent bond is

Bond length

  • The bond length is internuclear distance of two covalently bonded atoms
    • It is the distance from the nucleus of one atom to another atom which forms the covalent bond


  • The greater the forces of attraction between electrons and nuclei, the more the atoms are pulled closer to each other
  • This decreases the bond length of a molecule and increases the strength of the covalent bond
  • Triple bonds are the shortest and strongest covalent bonds due to the large electron density between the nuclei of the two atoms
  • This increase the forces of attraction between the electrons and nuclei of the atoms
  • As a result of this, the atoms are pulled closer together causing a shorter bond length
  • The increased forces of attraction also means that the covalent bond is stronger


Triple bonds are the shortest covalent bonds and therefore the strongest ones