Predicting melting points of substances based on their molecular/atomic structure Wouldn't it be great to be able to predict the melting point of a metal based on the atomic number and not by looking in some table for the value that was measured experimentally by someone else? Or to predict the same melting point for a simple salt like NaCl or KI by applying some formula to the atomic numbers of the 2 atoms involved? 

Can you help me understand why is it so difficult to build a theoretical model for this particular physical property? Were there attempts made in the scientific world for such a model?

--EDIT--

Yes, this is part of my question: 
I want to understand if there is a connection between the theoretical explanations of properties like melting point and the current theoretical model of atomic structure. Can the electronic structure of $\ce{Fe 1s^2 2s^2 2p^6 3s^2 3p^6 3d^6 4s^2}$ tell us anything about it's probable melting point without measuring that point in the first place?
With regard to organic compounds, you might be interested in group contribution methods, e.g. the Joback method.

These methods divide a molecule into functional groups or similar small building blocks and estimate the melting point (and other thermodynamic properties) based on the contributions of the individual groups.