AS-Level Bonding


  • Atoms can bond together to create larger species.

  • Bonds that hold atoms together are called atomic bonds. 

  • Forces between molecules are called intermolecular forces.

    • Intermolecular forces are broken and formed when molecular substances change state (solid, liquid and gas) 




There are only 118 elements in the periodic table, yet there are millions of different substances on planet earth. The abilities of elements to react together and ‘combine’ with each other gives rise to these millions of different substances.

Atomic bonds are bonds that exist between atoms within a compound.

Intermolecular forces are forces that arise between molecules. These forces ‘hold’ molecules together and cause them to exist in either a solid or liquid state.

There are three types of atomic bond:

  • Covalent

  • Ionic

  • Metallic


There are three key types of intermolecular forces:

  • Instantaneous, temporary induced, dipole-dipole

  • Permanent dipole-dipole

  • Hydrogen bonding

Molecular substances are held together by intermolecular forces when in solid and liquid state.


It is these forces that get broken when molecular substances change state - not the covalent bonds in the molecules themselves.