Bond Length & Bond Strength (Edexcel A Level Chemistry): Revision Note

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