Question

How to figure out which melting point would have the lowest melting point ?

Answer 1

Answer:

That would be helium, with a melting point of 0.95 K (-272.20 °C)—although this happens only under considerable pressure (~25 atmospheres). At ordinary pressure, helium would remain liquid even if it could be chilled to absolute zero.

Answer 2

Answer:

By evaluating the intermolecular forces and size!

Explanation:

Essentially the stronger the forces the higher the melting point... Here is a list of interemolecular forces (the first will be the weakest).

1) Dispersion forces (Exhibited by evrey molecule) (Weakest)

2) Dipole-Dipole

3) Hydrogen bonding

4) Ionic bonds (Strongest)

The stronger the forces it has then the higher the melting point. Also aromatic structures have a higher melting point as well. A general rule of thumb is, the larger the structure is then the higher thee melting point it.