Order the intermolecular forces (dipole-dipole, london dispersion, ionic, and hydrogen-bonding) from weakest to strongest.

London dispersion < dipole-dipole < hydrogen-bonding < ionic

Explanation:

Inter-molecular forces of attraction are the forces that facilitate interaction between the solute and solvent molecules and affect their solubility. They broadly classified as follows:  

Ionic: This is the strongest force of attraction which exist between a charged atoms or molecules i.e. positive and negative ions.

Hydrogen bonds: These are forces of attraction which operate in molecules containing an electronegative atom like oxygen, nitrogen or fluorine directly attached to a hydrogen atom.

Dipole-dipole: These operate in molecules which have a permanent dipole i.e. between polar molecules

Dispersion or London forces: This is the weakest intermolecular force which occurs in non-polar molecules through the creation of an instantaneous or a temporary dipole

The order of inter-molecular forces from weakest to strongest is:

London dispersion < dipole-dipole < hydrogen-bonding < ionic

they are made of gases.

they have a spherical shape.

they make energy through fusion.