Edexcel A Level Chemistry:复习笔记1.4.7 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